A small grill can hold two hamburgers at a time. If it takes 10 minutes to cook one side of a hamburger, and 5 minutes to cook the other side, then what is the shortest time needed to cook both sides of three hamburgers? (HINT: You are allowed to cook one side of a hamburger and then set it aside before cooking the other side.)

Answer 1

30

Answer 2

The actual answer is 25!

Answer 3

a can that contains 5 red balls and 3 green ball has a mass of 43g
when the can contains3red balls and 5 green balls the mass is37g
when the can contains 1 red ball and 1 green ball the mass is 19 g
what is the mass of the can and each ball