Arthur D. answered • 11/19/14

Forty Year Educator: Classroom, Summer School, Substitute, Tutor

Nenalyn B.

asked • 11/19/14Pipe A fills a 5liter tank at a rate of 15liter per hour. Pipe B fills the same thank at a rate of 10 l/h. Pipe A runs alone for 100 minutes then the two of them together finish filling up the tank. How long does the whole operation take?

Follow
•
2

Add comment

More

Report

Arthur D. answered • 11/19/14

Tutor

4.9
(70)
Forty Year Educator: Classroom, Summer School, Substitute, Tutor

the first pipe fills 15 L in one hour

the first pipe runs for 100 minutes or 100/60=1 40/60 hours, or 1 2/3 hours

the first pipe fills 15*(1 2/3)=25 L in that 100 minutes

there are now 50-25=25 L to be filled by both pipes

one pipe fills 15 L in one hour

the second pipe fills 10 L in one hour

in one hour the first pipe fills 15 L and the second pipe fills 10 L for a total of 25 L in one hour, but that was how much was left to be filled by both pipes working together

therefore, after 1 more hour the tank is filled

the first pipe worked for 100 minutes or 1 2/3 hours and then both pipes worked together for 1 more hour for a total time of 1+1 2/3=2 2/3 hours

Bob A. answered • 11/19/14

Tutor

4.9
(127)
20 Years Making Science and Maths Understandable and Interesting!

Are we supposed to go by the title of this request or the actual description written?

The title says 50 liter but the title is incorrect English.

A reading of the title, especially the first phrase, makes no sense.

The description written out is correct English with complete sentences.

Let's assume that description is the real question.

It says a 5 liter tank.

If pipe A fills a 5 liter tank at 15 l/hr and runs for 100 min. (1 hr 40 min) it will fill the tank in 20 min. and overflow the 5 liter tank for the rest of the time. Pipe B won't be needed.

Ask a question for free

Get a free answer to a quick problem.

Most questions answered within 4 hours.

Find an Online Tutor Now

Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.