Assume that a milliliter of water contains 20 drops. How long, in hours, will it take you to count the number of drops

of water in 1.0 gal of water at a counting rate of 10 drops/s?!

126.18 hr

Explanation:

Data given:

1 mL of water = 20 drops

count rate = 10 drops/s

time in hours for one gallon = ?

Solution:

First we calculate number of mL (milliliter) of water in gallon

As we know

1 gallon = 3785.4 mL

As,

1 galon consist of 3785.4 mL of water, so now we count number of drops that contain 3785.4 mL of water

As we Know 1 mL water contain 20 drops then 3785.4 mL of water contain how many drops:

Apply unity formula

1 mL water ≅ 20 drops

3785.4 mL water ≅ X drops

Do cross multiplication

X drops of water = 20 drops x 3785.4 mL / 1 mL

X drops of water = 75708 drops

So, we come to know that one gallon contain 75708 drops of water and we have to calculate the time in hour to count these drops

First we calculate time in seconds

As we Know 10 drops water count in one second then how many seconds it will take to count 75708 drops

Apply unity formula

1 second ≅ 10 drops

X second ≅ 75708 drops

Do cross multiplication

X second = 1 second x 75708 drops / 10 drops

X second = 7570.8 second

So it take 7570.8 second to count 1 gallon water drops

Now convert seconds to hours

As,

60 seconds = 1 hr

7570.8 second = 7570.8 / 60 = 126.18 hr

So it take 126.18 hr to count 1 gallon water drops.