Question

if 30 men working 7 hours a day can do a piece work in 18 days,in how many days will 21 men working 8 hours a day to do same work

Answer 1

Let required days be n.
30 × 7 × 18 = 21 × 8 × n
n = 30 × 7/21 × 18/8 = 180/8 = 45/2 days

Answer 2

Answer:

This is right answer 45/2 days

Step-by-step explanation:

Let required days be x.

30 men working 7 hours a day can do a piece work in 18 days=30 × 7 × 18

days will 21 men working 8 hours a day to do same work=21 × 8 × x

30 × 7 × 18 = 21 × 8 × x

X=30 × 7/21 × 18/8 = 180/8 = 45/2 days