SSC GD 2019 PYQ — Question 59

SSC GD Constable (English) - 13 Feb 2019 Shift 3 • Quantitative Aptitude • Q59

M can complete a work in 14 days less than the time taken by L. If both M and L together can complete the same work in 24 days, then in how many days M alone can complete the same work?

Show answer & explanation

Correct answer: B

Explanation

The correct answer is option 2 i.e. 56 days.

Understanding/Application

Let the number of days taken by L to complete the work be L days.

1 day work of L = 1/L

Number of days taken by M to complete the work = L - 14

ATQ - 

(1/L) + 1/(L - 14) = 1/24

(2L - 14)/(L2 - 14L) = 1/24

L2 - 62L + 336 = 0

L2 - 6L - 56L + 336 = 0

L(L - 6) -56(L - 6) = 0

(L - 56) (L - 6) = 0

L = 56 or 6

M can do work in 14 days less than L so L cannot be 6.

L can do the work in 56 days.