9514 1404 393
Answer:
 5
Explanation:
When y varies inversely as x, the relation is ...
 y = k(1/x) = k/x
Multiplying by x gives ...
 xy = k
The value of k can be found from (x, y) = (10, 10):
 (10)(10) = k = 100
Then the new value of x will be ...
 x(20) = 100
 x = 100/20 = 5