TIME AND WORK

TIME AND WORK

If M1 person can do W1 work in D1 days and M2 person can do W2 works in D2 days then we can say M1 D1 W2 = M2 D2 W1

For Time T

M1 D1 T1 W2 = M2 D2 T2 W1

For Efficiency E

M1 D1 T1 E1 W2 = M2 D2 T2 E1 W1

The Only exchange in formula is work W

If A can do a piece of work in n days,Then the works done by a in one day =1 / N

If A one day work is 1 / N the work finished by A in N days

A is 4 times Eficien then B==>4A=B

A:B=4:1

If A can do a work in D1 days and B can do the same work in D2 days then A and B together can do the same work in 

(D1 * D2) / (D1 + D2)

If A can do a piece of work in D1 days,B can do in D2 days C in D3 days then together the same work in

(D1+D2+D3) / (D1D2 +D2D3+D3D1)

If A and B can do piece of work in D1 alone D2,B alone Can=?

(D1*D2) / (D2-D1)

If the number of men are changed in ratio M:N the time taken to complete the work will change in the ratio N:M

Eg:

 A can do a piece of work in 14 days which b can do in 21 days.They begin together but 3 days before the completion the work ,A leaves off.The total number of days to complete the work is?

A=14 Days

B=21 Days

Total work=LCM(14,21)

                  =42

A's One day work=42/14=3

B's One day work=42/21=2

A+B One day work =5

Before 3 days A leaves=42-3=39

39 work done by A+B=39/5=7.8

total working days=7.8+remaining days=10.8