Question

what should be substracted from thrice the rational number -8/3 to get 5/2?

Answer 1

Let the number to be subtracted be x.
As per the question,
3* -8/3 - x = 5/2
-8-x = 5/2
-16-2x = 5
2x = -21
x = -21/2.

So, required number = -21/2.