Question

2 men can build a wall in 15 and 20 hours respectively but if they work together they use 280 less brick per hour and build a wall in 12 hours. Find the bricks in the wall?

Answer 1

Answer:

Number of bricks in the wall is 8400.

Step-by-step explanation:

Given : 2 men can build a wall in 15 and 20 hours respectively but if they work together they use 280 less brick per hour and build a wall in 12 hours.

To Find : The bricks in the wall?

Solution :

Let 1st men be A build in 15 hours.

Let 2nd men be B build in 20 hours.

Total work done by A and B is the LCM of 15 and 20.

LCM(15,20)=60

Now,

Efficiency of A is $\frac{60}{15}=4$

Efficiency of B is $\frac{60}{20}=3$

When they work together per hour work is 7x.

If they work together they use 280 less brick per hour and build a wall in 12 hours.

i.e. $\frac{60}{12}x=5x$

According to question,

$7x-5x=280$

$2x=280$

$x=140$

Number of bricks in the wall is $60\times 140=8400$

Therefore, Number of bricks in the wall is 8400.

Answer 2

short & simple

hope this is helpful for you