A rental Company can set up 3 small tents and 1 large tent in 115 min. They can set up 2 small tents and 2 large tents in 130 min. How much time is required to set up a small tent ?

The correct answer is: 25 min

Complete step by step solution:
Let’s take the time required to make one small tent = s minutes
And let the time required to make one large tent = l minutes

Let 3s + 1l = 115 minutes…(i)

 and 2s + 2l = 130 minutes….(ii)
On multiplying (i) with 2, we get 2(3s + 1l = 115)

                                   ⇒ 6s + 2l = 230…(iii)
Now, we have the coefficients of l in (ii) and (iii) to be the same.
On subtracting (ii) from (iii),
we get LHS to be 6s + 2l - (2s + 2l) = 6s - 2s = 4s
and RHS to be 230 – 130 = 100
On equating LHS and RHS, we have 4s = 100

                                               ⇒ s = 25
On substituting the value of s in (ii), we get 2 × 25 + 2l = 130

                                              ⇒ 50 + 2l = 130

                                               ⇒ 2l = 130 - 50

                                               ⇒ 2l = 80

                                                ⇒ l = 40
Hence we get s = 25 and l = 40
Hence time to set up small tent = 25 minutes
and time to set up large tent = 40 minutes
Here, option B is the right answer.
25 minutes is time required to set up a small tent.
Note: We can also solve these system of equations by making the coefficients of s
to be the same in both the equations.