Question

20 men can complete a piece of work in 20 days. If 30 men and 12 women under take to complete the work, the work will be completed in : 

(a) 10 days 

(b) 12 days 

(c) 15 days 

(d) 16 days

Answer 1

Correct option (a) 10 days

Explanation:

20M × 20 days = 24W × 20 days

So, (30M+12W) complete the whole work in

24W × 20 = (30M+12W) × x

24W × 20 = (36W+12W) × x

24W × 20 = 48W × x 

x = 10 days

Alternate :

20 M × 20 days = 24W × 20 days

5 M = 6W 

M/W = 6/5

Total work = 20 × 6 × 20 units

Efficiency of (30M + 12W)

=30 × 6 + 12 × 5

= 180 + 60 = 240 

Required no. of days = 20 x 6 x 20/240 = 10 days