The average number of playing cards Justin and Warren had was 457. The average number of playing cards Justin and Jenson had was 227. If the ratio of Warren's playing cards to Jenson's playing cards was 7 : 2, find the number of playing cards Justin had.
Total number of cards that Justin and Warren had
= 2 x 457
= 914

Total number of cards that Justin and Jenson had
= 2 x 227
= 454

Number of playing cards Warren had = 7 u
Number of playing cards Jenson had = 2 u

Justin's cards + 7 u = 914 --- (1)
Justin's cards + 2 u = 454 --- (2)

(1) - (2)
7 u - 2 u = 914 - 454
5 u = 460
1 u = 460 ÷ 5 = 92

Number of playing cards that Jenson had
= 2 u
= 2 x 92
= 184

Number of playing cards that Justin had
= 454 - 184
= 270

Answer(s): 270