Answer:
Equivalent ratio states that the two ratios are express the same relationship between numbers
As per the given statement: Curtis threw 15 darts at a dashboard.
40% of his darts hit the bull's eye
then;
60 % of his darts did not hit the bull's eyes.
By definition of equivalent ratio;

Multiply both sides by 15 we have;

Therefore, 9 darts did not hit the bull's-eye.