Important Formulas - Time and Work - Tricks & Shortcuts

1) If A can do a piece of work in n days, work done by A in 1 day = 1/n

2) If A does 1/n work in a day, A can finish the work in n days

3) If M1 men can do W1 work in D1 days working H1 hours per day and M2 men can do W2 work in D2 days working H2 hours per day (where all men work at the same rate), then

(M1 D1 H1 / W1) = (M2 D2 H2 / W2)

4) If A can do a piece of work in p days and B can do the same in q days, A and B together can finish it in pq / (p+q) days

5) If A is thrice as good as B in work, then

Ratio of work done by A and B = 3 : 1

Ratio of time taken to finish a work by A and B = 1 : 3

6) If A can do a work in ‘x’ days and B can do the same work in ‘y’ days, then the number of days required to complete the work if A and B work together is: (x*y)/(x+y)

7) If A can do a work in ‘x’ days and A + B can do the same work in ‘y’ days, then the number of days required to complete the work if B works alone is: (x*y)/(x-y)


Quantitative Aptitude & Data Interpretation