Explain why any rational number is either a terminating or repeating decimal?

Because if the number was rational then we can tell by looking at the numbers. The rational number should be one number or a repeating decimal or terminating number. plus because if a number was like this 5.7696... that means its irrational because we dont know the end of the number. The rational numbers are terminating numbers or either decimal or repeating numbers because we know the end of those numbers. 

It is 1 cup to 2 lbs