Time and Work:
This topic is very much needed when you want to know how many person can complete the task with in how many days or how long it will take to complete the given work or how much work one person can do etc. for this kind of questions we will provide the short cut way to solve it.
1. If a person can do a piece of work in ‘X’ days, then person one day work is (1 / X)
2. If a person 1 day’s work is (1 / X) then the person will complete the work in ‘X’ days.
3. While solving the problems assume the work done by person to be equal to 1.
Previous year solved Questions:
1. A alone can do a piece of work in 6 days, B alone can do the same work in 12 days. In how many days can A and B together completes the same work?
A) 5 days B) 4 days C) 3 days D) 2 days E) None of these
Solution: A’s 1 day’s work = (1 / 6)
B’s 1 day’s work = (1 / 12)
(A + B)’s 1 day’s work = (1 / 6) + (1 / 12) = (1 / 4)
Therefore (A + B) will complete the work in 4 days.
2. 3 men can do a piece of work in 18 days. 6 children can also do that work in 18 days. 4 men and 4 children together will finish the work in how many days?
A) 10 B) 6 C) 12 D) 9 E) None of these
Solution: Using the below formulae M1D1W2 = M2D2W1
=> 3 * 18 * 1 = 6 * D2 *1
=> D2 = 9 days
3. Ravi gets Rs. 110 for every day that he works. If he earns Rs. 2750 in a month of 31 days, for how many days did he work?
A) 25 days B) 28 days C) 26 days D) 24 days E) None of these
Required number of days = (2750 / 11) = 25 days