The average number of playing cards Japheth and Henry had was 477. The average number of playing cards Japheth and Dylan had was 228. If the ratio of Henry's playing cards to Dylan's playing cards was 5 : 2, find the number of playing cards Japheth had.
Total number of cards that Japheth and Henry had
= 2 x 477
= 954

Total number of cards that Japheth and Dylan had
= 2 x 228
= 456

Number of playing cards Henry had = 5 u
Number of playing cards Dylan had = 2 u

Japheth's cards + 5 u = 954 --- (1)
Japheth's cards + 2 u = 456 --- (2)

(1) - (2)
5 u - 2 u = 954 - 456
3 u = 498
1 u = 498 ÷ 3 = 166

Number of playing cards that Dylan had
= 2 u
= 2 x 166
= 332

Number of playing cards that Japheth had
= 456 - 332
= 124

Answer(s): 124