SSC CGL 2020 PYQ — Question 10

SSC CGL Tier II - Quant - 15 Nov 2020 • Quantitative Aptitude • Q10

Three man and 4 women can do a piece of work in 7 days, whereas 2 men and 1 women can do it in 14 days. Seven women will complete the same work in:

Show answer & explanation

Correct answer: A

Explanation

The correct answer is option 1 i.e. 10 days

Concept

Since the work is same,  we need to equate work in both cases which is given by :

M1D1 = M2D2

Here M1 and M2 represent number of men

D1 and D2 represent number of days.

Application

 (3 men + 4 women) × 7 = (2 men + 1 women) × 14

(3 men + 4 women)  = (2 men + 1 women) × 2

 3 men + 4 women = 4 men + 2 women

2 women = men

(women ∶ men) = 1 : 2

Efficiency Ratio of (women ∶ men)  = 1 ∶ 2

We know that

Total Work = Efficiency × Time

(3 men + 4 women) × 7 = (2 men + 1 women) × 14 

(3 × 2 + 4 × 1) × 7 = (2 × 2 + 1 × 1) × 14 = 70

Total Work = 70

number of days taken to complete the work by 7 women = Total work/Efficiency

70 / (7 × 1)

10 days