Correct Answer - Option 2 : 7 days
Given
Sunita can finish a project in = 21 days
Sarita can finish the same project in = 15 days
Sarita worked on the project for days = 10 days
Formula used
Work = Time × Efficiency
Calculation
Sarita’s 10 days work = 1/15 × 10 = 2/3
Remaining work = 1 - (2/3) = 1/3
Sunita can finish a project in = 21 days
Now ,
1/21 Work done by Sunita in = 1 day
1/3 works can be done by Sunita in = 21 × 1/3 = 7 days
∴ Sunita will finish the remaining work in 7 days.
