Use Problem Solving Strategies to Solve the Problem

Multiple Choice

Use problem solving strategies to solve the problem.
-What's the easiest way to heat a pan of water for 9 minutes when you have only a 6-minute hour-glass timer and a 21-minute hour-glass timer?

A) Start both timers. When the 6-min one runs out, turn it over. When it runs out again, start heating the water until the 21-min timer runs out.
B) Start the 6-min timer. When it's halfway through start heating the water. When it runs out turn it over and heat the water until it runs out again.
C) Can't be done.
D) Start both timers. When the 6-min timer runs out, start heating the water. Continue until the 21-min timer runs out.