whats the value of n

Question

Three tanks A,B and C are used to store oil. Tank A contains "n" litres of oil. Tank B contains (n+150) litres of oil. Tank C is empty. Oil is pumped from Tank A and from Tank B into Tank C so that all three Tanks contain the same amount of oil. 500 litres of oil are pumped from Tank A into Tank C. Workout the value of "n"

Answer 1

Use n - 500 for the amount left in A

 

Use n + 150 -y for the amount left in B

 

Use 500 + y for the amount left(final amount) in C

 

Pick two to set equal to each other:

 

n + 150 - y = 500 + y

 

Solve for y in terms of n:

 

y = n - 350

       2

 

Substitute:

 

500 + n - 350 = n - 500

             2

 

Solve for n

 

n = 1650 = amount in A

 

1650 - 500 = 1150 This is the amount in each tank at the end.

 

1650 + 150 - y = 1150

 

Solve for y:

 

y = 650

 

amount in C = 500 +y = 500 + 650 = 1150  Yes.

amount in B = n + 150 - y = 1650 + 150 - 650 = 1150  Yes.