What is the rule for the reflection

The volume of gas a balloon can hold varies directly as the cube of its radius. imagine a balloon with a radius of 3 inches can hold 81 cubic inches of gas. how many cubic inches of gas must be released to reduce the radius down to 2 inches?

Find the value of the combination. 5 c 5

Betty correctly answers 30 questions on your math test there are 40 questions on the test what percent of the questions did she answered incorrectly