If you would like to know how much orange juice can Bob make, you can calculate this using the following steps:
2 cups of orange juice concentrate ... 1 orange juice
6 cups of orange juice concentrate ... x = ?
2 * x = 1 * 6
2 * x = 6 <-- now divide 2 to the other side
x = 6/2
x = 3
The correct result would be 3.