Correct Answer - Option 2 : 4
Given,
Number of days taken by Newton to complete the work by working 7 hours = 10 days
Number of days taken by Edison to complete the work by working 5 hours = 7days
Concept used,
If someone completes work in x days
∴ Work done in 1 day = 1/x
Calculation
∵ Newton takes 10 days to complete by working 7 hours a day.
∴ Newton takes 70 hours to complete the work.
∴ Newton’s 1 hour’s work = 1/70
∵ Edison takes 7 days to complete by working 5 hours a day.
∴ Edison takes 35 hours to complete the work.
∴ Edison’s 1 hour’s work = 1/35
1 hour’s work of Newton and Edison together = 1/70 + 1/35
= 3/70
Let Newton and Edison takes X days to complete.
∴ (35/6) × (3/70) × X = 1
⇒ X/4 = 1
⇒ X = 4
∴ Newton and Edison take 4 days to complete the work.
