Zoe, Usha and Jaslyn have equal number of coins. Zoe packs all her coins equally into 7 packets. Usha packs all her coins equally into 4 packets. Jaslyn packs all her coins equally into 8 packets. 2 packets of Zoe's coins, 3 packets of Usha's coins and 4 packets of Jaslyn's coins add up to 860 coins. How many coins do they have altogether?

	Zoe	Usha	Jaslyn
Number of packets	7	4	8
Number of coins	56 u	56 u	56 u
Number of coins in each packet	8 u	14 u	7 u

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

All the children have equal numbers of coins. 
Make the number of coins that each child has the same. LCM of 7, 4 and 8 = 56

Number of coins that each child has = 56 u

Number of coins in 1 packet of Zoe's coins = 56 u ÷ 7 = 8 u
Number of coins in 1 packet of Usha's coins = 56 u ÷ 4 = 14 u
Number of coins in 1 packet of Jaslyn's coins = 56 u ÷ 8 = 7 u

Number of coins in 2 packets of Zoe's coins, 3 packets of Usha's coins and 4 packets of Jaslyn's coins
= (2 x 8 u) + (3 x 14 u) + (4 x 7 u)
= 16 u + 42 u + 28 u
= 86 u

86 u = 860

1 u = 860 ÷ 86 = 10

Total number of coins that they have
= 3 x 56 u
= 168 u
= 168 x 10
= 1680

Answer(s): 1680