Cassy can pack 12 x 10 = 120 jars of jam in the 10 boxes. She can also pack 10 x 30 = 300 jars of jam in the 30 boxes. A total of 300 + 120 = 420 jars of jam can be packed in the boxes. So, 500 - 420 = 80 jars of jam will be left unpacked.is the reasoning for what question and answer pair?
Q: Cassy packs 12 jars of jam in 10 boxes while she packs 10 jars of jam in 30 boxes. If she has 500 jars of jams, how many jars of jam will she have left when all the boxes are full?
A: 80