Answer:
r=2
Step-by-step explanation:
y = k x^r is the formula for a direct variation
y = k x^ -r is the formula for a indirect variation
20= 5 (1/2)^ -r
Divide each side by 5
4 = (1/2) ^ -r
Rewriting
2^2 = 2^ -1 ^ -r
2^2 = 2 ^ r
The bases are the same so
2 =r
