Maria wants to find the product of 5 3/20 x 3 4/25 using decimals instead of fractions. How can she rewrite the problem using decimals?

Atreasure chest sinks at a rate no less than 20 feet er second. the floor of the icean is at most at -4,200 feet. will the tresure chest reach the ocean floor in less than 3 minutes? explain.