Farra subtracted 5 from a number and then divided by 4. Next, he subtracted 4 from the original number and then divided by 5. He got the same final answer both times. What was the original number?
Set x as the original number.
Write out equations:
x−54=x−45
Cross-multiply:
(x−5)5=(x−4)4
Simplify to...
5x−25=4x−16
Solve the equation by subtracting 4x from both sides:
x−25=−16
Then add 25 on both sides:
x=−16+25=9
So the final answer would be x=9