Answer:
(Choice B) B It decreases.
Explanation:
According to the situation, the solution of the value of the expression is as follows
Let us assume
r 80 -2r
5 80 - 10 = 70
4 80 - 8 = 72
3 80 - 6 = 74
2 80 - 4 = 76
1 80 - 2 = 78
As we can from the above calculation that expression value risen if r value decreased
Therefore the correct option is B.