Joelle, Rachel and Kimberly have equal number of stickers. Joelle packs all her stickers equally into 8 packets. Rachel packs all her stickers equally into 10 packets. Kimberly packs all her stickers equally into 4 packets. 3 packets of Joelle's stickers, 7 packets of Rachel's stickers and 2 packets of Kimberly's stickers add up to 378 stickers. How many stickers do they have altogether?

	Joelle	Rachel	Kimberly
Number of packets	8	10	4
Number of stickers	40 u	40 u	40 u
Number of stickers in each packet	5 u	4 u	10 u

All the stickers can be put into the packets without remainder.

All the children have equal numbers of stickers. 
Make the number of stickers that each child has the same. LCM of 8, 10 and 4 = 40

Number of stickers that each child has = 40 u

Number of stickers in 1 packet of Joelle's stickers = 40 u ÷ 8 = 5 u
Number of stickers in 1 packet of Rachel's stickers = 40 u ÷ 10 = 4 u
Number of stickers in 1 packet of Kimberly's stickers = 40 u ÷ 4 = 10 u

Number of stickers in 3 packets of Joelle's stickers, 7 packets of Rachel's stickers and 2 packets of Kimberly's stickers
= (3 x 5 u) + (7 x 4 u) + (2 x 10 u)
= 15 u + 28 u + 20 u
= 63 u

63 u = 378

1 u = 378 ÷ 63 = 6

Total number of stickers that they have
= 3 x 40 u
= 120 u
= 120 x 6
= 720

Answer(s): 720