1 Answers
Option 1 : 64 days
Given:
Jaya and Shushma can complete the work together in 40 days
Jaya worked for 15 days with Sushma and left afterwards
The remaining work is done by Shushma in 40 days
Concept used
If a person does the work in x days then work done by the person in 1 day = 1/x of total work.
Calculation:
Work completed by Jaya and Shushma together in 1 day = 1/40
Work completed by them in 15 days = 15/40 = 3/8
Remaining work = 1 – 3/8 = 5/8
According to the question, Shushma can complete 5/8 work in 40 days
Shushma can complete 1 work in 40 × 8/5 = 64 days
∴ Shushma can complete the whole work alone in 64 days
Shortcut Trick
Formula used:
M1D1 = M2D2
Here, M and D are the person who is working and time taken respectively
Time = Total work/Efficiency
Calculation:
Now, According to question,
Considering the first letter of Jaya and Shushma as their respective unit work
(J + S) × 40 = (J + S) × 15 + 40S
⇒ (J + S) × 25 = 40S
⇒ 25J = 15S
⇒ J = (3/5)S
Time is taken to do work alone by Shushma = {(J + S) × 40}/S
= {((3/5)S + S) × 40}/S
= (8/5) × 40
= 64
∴ Shushma can complete the whole work alone in 64 days