You are here:

Calculus/Simultaneous equations

Advertisement


Question
I am really struggling with this word problem, I have trouble in setting up the expressions.
you have a pool with 3 pipes to fill it with.
pipes A and B take 4hrs to fill the pool,
pipes B and C take 3.75hrs to fill the pool,
and
pipes A, B, and C take 3hrs.
how many hours would it take each pipe individually to fill the pool.

Answer
Questioner:Roger
Country:Iowa, United States
Category:Calculus
Private:No
Subject:pre-calc
Question:

I am really struggling with this word problem, I have trouble in setting up the expressions.
you have a pool with 3 pipes to fill it with.
pipes A and B take 4hrs to fill the pool,
pipes B and C take 3.75hrs to fill the pool,
and
pipes A, B, and C take 3hrs.
how many hours would it take each pipe individually to fill the pool.
....................................................
Try this approach:

Let a = the flow rate of pipe A, in pph.*
   b = ......................B.........
   c = ......................C.........

* pph = 'pools per hour'

pipes A and B take 4hrs to fill the pool, means:
a + b = 1/4  pph

pipes B and C take 3.75hrs to fill the pool,means
b + c = 1/3.75 = 4/15  pph


and
pipes A, B, and C take 3hrs, means
a + b + c = 1/3   pph

Now you have three equations in three variables -- clear fractions and solve.

Calculus

All Answers


Answers by Expert:


Ask Experts

Volunteer


Paul Klarreich

Expertise

All topics in first-year calculus including infinite series, max-min and related rate problems. Also trigonometry and complex numbers, theory of equations, exponential and logarithmic functions. I can also try (but not guarantee) to answer questions on Analysis -- sequences, limits, continuity.

Experience

I taught all mathematics subjects from elementary algebra to differential equations at a two-year college in New York City for 25 years.

Education/Credentials
(See above.)

©2016 About.com. All rights reserved.