Maths-
General
Easy

Question

In a class of 35 students, 17 have taken Mathematics, 10 have taken Mathematics but not Economics. If each student has taken either Mathematics or Economics or both, then the number of students who have taken Economics but not Mathematics is

  1. (a) 7  
  2. 25  
  3. 18  
  4. 32  

The correct answer is: 18


    Let M and E denote the sets of students who have taken Mathematics and Economics respectively. Then, we have
    n open parentheses M union E close parentheses equals 35 comma n open parentheses M close parentheses equals 17 blank a n d blank n open parentheses M intersection E to the power of ´ end exponent close parentheses equals 10
    Now,
    n open parentheses M intersection E to the power of ´ end exponent close parentheses equals n open parentheses M close parentheses minus n left parenthesis M intersection E right parenthesis
    rightwards double arrow 10 equals 17 minus n open parentheses M intersection E close parentheses rightwards double arrow n open parentheses M intersection E close parentheses equals 7
    Now,
    n open parentheses M union E close parentheses equals n open parentheses M close parentheses plus n open parentheses E close parentheses minus n left parenthesis M intersection E right parenthesis
    rightwards double arrow 35 equals 17 plus n open parentheses E close parentheses minus 7 rightwards double arrow n open parentheses E close parentheses equals 25
    therefore n open parentheses E intersection M to the power of ´ end exponent close parentheses equals n open parentheses E close parentheses minus n open parentheses E intersection M close parentheses equals 25 minus 7 equals 18

    Related Questions to study

    General
    Maths-

    Let A be the set of all animals. A relation R is defined as " a R b iff a and b are in different zoological parks”. Then R is

    Let A be the set of all animals. A relation R is defined as " a R b iff a and b are in different zoological parks”. Then R is

    Maths-General
    General
    Maths-

    If A equals open curly brackets a comma b comma c comma l comma m comma n close curly brackets comma then the maximum number of elements in any relation on A is

    If A equals open curly brackets a comma b comma c comma l comma m comma n close curly brackets comma then the maximum number of elements in any relation on A is

    Maths-General
    General
    Maths-

    If A subset of or equal to B, then B union A is equal to

    If A subset of or equal to B, then B union A is equal to

    Maths-General
    parallel
    General
    Maths-

    If R is a relation on a finite set having n elements, then the number of relations on A is

    If R is a relation on a finite set having n elements, then the number of relations on A is

    Maths-General
    General
    Maths-

    Let A equals left curly bracket x colon x blankis a multiple of 3right curly bracket and B equals left curly bracket x colon x blank i s blank a blank m u l t i p l e blank o f blank 5 right curly bracket. Then, A intersection Bis given by

    Let A equals left curly bracket x colon x blankis a multiple of 3right curly bracket and B equals left curly bracket x colon x blank i s blank a blank m u l t i p l e blank o f blank 5 right curly bracket. Then, A intersection Bis given by

    Maths-General
    General
    Maths-

    Let R be a relation on a set A such that R equals R to the power of negative 1 end exponent comma then R is

    Let R be a relation on a set A such that R equals R to the power of negative 1 end exponent comma then R is

    Maths-General
    parallel
    General
    Maths-

    The relation R equals open curly brackets open parentheses 13 close parentheses comma left parenthesis 35 right parenthesis close curly brackets is defined on the set with minimum number of elements of natural numbers. The minimum number of elements to be included in R so that R is an equivalence relation, is

    The relation R equals open curly brackets open parentheses 13 close parentheses comma left parenthesis 35 right parenthesis close curly brackets is defined on the set with minimum number of elements of natural numbers. The minimum number of elements to be included in R so that R is an equivalence relation, is

    Maths-General
    General
    Maths-

    From 50 students taking examinations in Mathematics, Physics and Chemistry, 37 passed Mathematics, 24 Physics and 43 Chemistry. At most 19 passed Mathematics and Physics, at most 29 passed Mathematics and Chemistry and at most 20 passed Physics and Chemistry. The largest possible number that could have passed all three examinations is

    From 50 students taking examinations in Mathematics, Physics and Chemistry, 37 passed Mathematics, 24 Physics and 43 Chemistry. At most 19 passed Mathematics and Physics, at most 29 passed Mathematics and Chemistry and at most 20 passed Physics and Chemistry. The largest possible number that could have passed all three examinations is

    Maths-General
    General
    Maths-

    If A equals open curly brackets 1 comma blank 2 comma blank 3 comma blank 4 comma blank 5 close curly brackets comma blank B equals open curly brackets 2 comma blank 4 comma blank 6 close curly brackets comma blank C equals left curly bracket 3 comma blank 4 comma blank 6 right curly bracket, then left parenthesis A union B right parenthesis intersection C is

    If A equals open curly brackets 1 comma blank 2 comma blank 3 comma blank 4 comma blank 5 close curly brackets comma blank B equals open curly brackets 2 comma blank 4 comma blank 6 close curly brackets comma blank C equals left curly bracket 3 comma blank 4 comma blank 6 right curly bracket, then left parenthesis A union B right parenthesis intersection C is

    Maths-General
    parallel
    General
    Maths-

    Let A equals open curly brackets 1 comma blank 2 comma blank 3 comma blank 4 close curly brackets comma blank B equals left curly bracket 2 comma blank 4 comma blank 6 right curly bracket. Then, the number of sets C such that A intersection B subset of or equal to C subset of or equal to A blank union B is

    Let A equals open curly brackets 1 comma blank 2 comma blank 3 comma blank 4 close curly brackets comma blank B equals left curly bracket 2 comma blank 4 comma blank 6 right curly bracket. Then, the number of sets C such that A intersection B subset of or equal to C subset of or equal to A blank union B is

    Maths-General
    General
    Maths-

    If A equals open curly brackets theta blank colon cos invisible function application theta greater than negative fraction numerator 1 over denominator 2 end fraction comma 0 less or equal than theta less or equal than pi close curly brackets and
    B equals open curly brackets theta blank colon sin invisible function application theta greater than fraction numerator 1 over denominator 2 end fraction comma fraction numerator pi over denominator 3 end fraction less or equal than theta less or equal than pi close curly brackets comma then

    If A equals open curly brackets theta blank colon cos invisible function application theta greater than negative fraction numerator 1 over denominator 2 end fraction comma 0 less or equal than theta less or equal than pi close curly brackets and
    B equals open curly brackets theta blank colon sin invisible function application theta greater than fraction numerator 1 over denominator 2 end fraction comma fraction numerator pi over denominator 3 end fraction less or equal than theta less or equal than pi close curly brackets comma then

    Maths-General
    General
    Maths-

    In a class of 30 pupils 12 take needls work, 16 take physics and 18 take history. If all the 30 students take at least one subject and no one takes all three, then the number of pupils taking 2 subjects is

    In a class of 30 pupils 12 take needls work, 16 take physics and 18 take history. If all the 30 students take at least one subject and no one takes all three, then the number of pupils taking 2 subjects is

    Maths-General
    parallel
    General
    Maths-

    If A equals left curly bracket x blank colon x is a multiple ofblank 4 right curly bracket and,
    B equals left curly bracket x blank colon x blankis a multiple ofblank 6 right curly bracket, then A intersection B consists of multiples of

    If A equals left curly bracket x blank colon x is a multiple ofblank 4 right curly bracket and,
    B equals left curly bracket x blank colon x blankis a multiple ofblank 6 right curly bracket, then A intersection B consists of multiples of

    Maths-General
    General
    Maths-

    In a city 20% of the population travels by car, 50% travels by bus and 10% travels by both car and bus. Then, persons travelling by car or bus is

    In a city 20% of the population travels by car, 50% travels by bus and 10% travels by both car and bus. Then, persons travelling by car or bus is

    Maths-General
    General
    Maths-

    Let Y equals open curly brackets 1 comma blank 2 comma blank 3 comma blank 4 comma blank 5 close curly brackets comma blank A open curly brackets 1 comma blank 2 close curly brackets comma blank B equals left curly bracket 3 comma blank 4 comma blank 5 right curly bracket and ϕ denotes null set. If left parenthesis A cross times B right parenthesis denotes cartesian product of the sets A and B; then open parentheses Y cross times A close parentheses intersection left parenthesis Y cross times B right parenthesis is

    Let Y equals open curly brackets 1 comma blank 2 comma blank 3 comma blank 4 comma blank 5 close curly brackets comma blank A open curly brackets 1 comma blank 2 close curly brackets comma blank B equals left curly bracket 3 comma blank 4 comma blank 5 right curly bracket and ϕ denotes null set. If left parenthesis A cross times B right parenthesis denotes cartesian product of the sets A and B; then open parentheses Y cross times A close parentheses intersection left parenthesis Y cross times B right parenthesis is

    Maths-General
    parallel

    card img

    With Turito Academy.

    card img

    With Turito Foundation.

    card img

    Get an Expert Advice From Turito.

    Turito Academy

    card img

    With Turito Academy.

    Test Prep

    card img

    With Turito Foundation.