Question

50 labourers can dig a pond in 16 days how many labourers will be required to dig another pond double in size in 20 days?

Answer 1

Use formula ,
Mi × Di /Wi = Mf × Df /Wf
where M is no of labour D is no of days and W is the part of work

given ,
Mi = 50
Di = 16
Wi = 1
and Mf = ?
Df = 20
Wf = 2

50 x 16 /1 = Mf x 20/2

Mf = 80 labours


or we can do it an another method

50 laborers dig a pond in 16 days.
In 1 day the pond can be dig by 50 * 16 men .
To dig a pond double in size in one day = 50*16*2 men are required.

to dig the pond double in size in 20 days = 50*16*2/20 =800*2/20= 1600/20 = 80 men are required