Maths-
General
Easy
Question
Let 
and 
are two arithmetic sequences such that 
and 
then the value of 
is
- 8/3
- 3/2
- 19/8
- 2
Hint:
use the formula Sn = (n/2)( 2 a1 + (n-1)d)
for the summation.
The correct answer is: 19/8
19/8
given, s1=t1 ; s2 = 2t2
let s2- s1 = d1 and t2-t1 = d2
s2-s1 = 2t2-t1 = d1
given,
summation (i=1 to 10) si = summation ( i= 1 to 15) ti
=> (10/2)( 2s1 + 9 d1) = (15/2) (2t1 + 14 d2)
on solving, we get
2s1 +9d1 = 3t1 + 21 d2
substituting the values of s1, d1 and d2 into this equation, we get
2t1 + 9(2t2-t1)=3t1+21(t2-t1)
or
3t2=11t1
substituting the value of t2 into the equation (s2-s1)/(t2-t1) we get
(2t2-t1)/(t2-t1)= (22/3-1)/(11/3-1)
= 19/8
an A.P is a sequence of mathematical terms which have a common difference with their adjacent elements
Related Questions to study
Maths-
If a, b and c are three consecutive positive terms of a G.P. then the graph of y = ax2 + bx + c is
Nature of graph of a quadratic equation is given by its discriminant.
Here, a = a, b= ar, c = ar2 , where r is the common ratio of the GP
Given, a,b,c>0
If a, b and c are three consecutive positive terms of a G.P. then the graph of y = ax2 + bx + c is
Maths-General
Nature of graph of a quadratic equation is given by its discriminant.
Here, a = a, b= ar, c = ar2 , where r is the common ratio of the GP
Given, a,b,c>0
Maths-
If ln (a + c) , ln (c – a), ln (a – 2b + c) are in A.P., then :
an A.P is a sequence of mathematical terms which have a common difference with their adjacent elements
An = A1+(n-1)x d
A2= A1 + d
A3 = A1 + 2d
A3 = A2+d
A3-A2=A2-A1
If ln (a + c) , ln (c – a), ln (a – 2b + c) are in A.P., then :
Maths-General
an A.P is a sequence of mathematical terms which have a common difference with their adjacent elements
An = A1+(n-1)x d
A2= A1 + d
A3 = A1 + 2d
A3 = A2+d
A3-A2=A2-A1
chemistry-
Which of the following is a natural polymer
Which of the following is a natural polymer
chemistry-General
chemistry-
Which of the following is an example of condensation polymer
Which of the following is an example of condensation polymer
chemistry-General
chemistry-
Which of the following is thermoplastic
Which of the following is thermoplastic
chemistry-General
chemistry-
Among the following a natural polymer is
Among the following a natural polymer is
chemistry-General
chemistry-
Melmoware are
Melmoware are
chemistry-General
chemistry-
Which of the following is not a polymer
Which of the following is not a polymer
chemistry-General
chemistry-
Which of the following is not a polymer
Which of the following is not a polymer
chemistry-General
chemistry-
‘Shellac’ secreted by lac insects is
‘Shellac’ secreted by lac insects is
chemistry-General
chemistry-
‘Cis-1, 4-polyisoprene’ is
‘Cis-1, 4-polyisoprene’ is
chemistry-General
chemistry-
Thermoplastics are
Thermoplastics are
chemistry-General
chemistry-
The basis on the mode of their formation, the polymers can be classified
The basis on the mode of their formation, the polymers can be classified
chemistry-General
chemistry-
Which one among the following is a thermosetting plastic
Which one among the following is a thermosetting plastic
chemistry-General
chemistry-
The end product of the reaction 
is
The end product of the reaction is
chemistry-General
