Question

If 2 pumps working 7 hours a day can lift 2,800 gallons of wayer in 20
days, in how many days can 20 pumps working 9 hours a day life 3,000
gallons of water?​

Answer 1

Given that

2 pumps working 7 hours a day can lift 2,800 gallons of water in 20 days

To Find :-

In how many days can 20 pumps working 9 hours a day life 3,000 gallons of water?

Solution :-

2 pumps working 7 hours a day = pumps work for 14 hours per day. ------(1)

Again,

2800 gallons of water lift in 20 days.

• It means, 140 gallons of water lift in 1 day. ------(2)

From equation (1) and (2), we concluded,

• 140 gallons of water is lifted in 14 hours.

So, In 1 hour, 140 ÷ 14 = 10 gallons of water is lifted.

According to statement,

20 pumps working 9 hours per day = pumps works for 180 hours per day.

Now,

• In 1 hour, 10 gallons of water is lifted.

So,

In 180 hours,

• 180 × 10 = 1800 gallons of water is lifted.

It implies,

• 1800 gallons of water is lifted in 1 day.

So,

3000 gallons of water is lifted in

$\: \: \rm = \: \: \dfrac{3000}{1800}$

$\: \: \rm = \: \: 1.666 \: days$