This is the question, but i get the wrong answer.

Question

In a theatre, 1/5 of the audience were under the age of 50 and 1/4 of the audience were over 75. What fraction of the whole audience were between 50 and 75 inclusive.

I simply used 1 - 1/5 - 1/4 = 11/20
but the correct answer should be 9/20...

why???

Answer 1

1/5 + 1/4 = 4/20 + 5/20 = 9/20 is over 50 or over 75

1 - 9/20 = 11/20 is between 50 and 75.

I got the same answer that you did.

Is it possible that the "correct" answer is wrong?

Please check back to see if a math tutor can shed some light on this answer.

Answer 2

1/5 + x + 1/4 = 1

multiply by 20

4 + 20x + 5 = 20
20x = 9
x = 9/20

Answer 3

there seems to be an error in Reiny's calculation.

4 + 20x + 5 = 20

20x = 20 - 4 - 5 = 11

20x ≠ 9

x = 11/20

I agree with Ms. Sue.

Answer 4

Yes, I am wrong.

Geesh, can't even subract 20 - 9 , lol
time for a nap.