Estimate x- and y- intercepts of the graph

Prove that the sum of two consecutive exponents of the number 5 is divisible by 30.if two consecutive exponents are 5n and 5n + 1, then their sum can be written as 30.

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?

Ametal rod is 2/5 meters long. it will be cut into pieces that are each 1/30 meters long. how many pieces will be made from the rod?