The average number of playing cards Flynn and Jeremy had was 422. The average number of playing cards Flynn and Vaidev had was 242. If the ratio of Jeremy's playing cards to Vaidev's playing cards was 7 : 2, find the number of playing cards Flynn had.
Total number of cards that Flynn and Jeremy had
= 2 x 422
= 844

Total number of cards that Flynn and Vaidev had
= 2 x 242
= 484

Number of playing cards Jeremy had = 7 u
Number of playing cards Vaidev had = 2 u

Flynn's cards + 7 u = 844 --- (1)
Flynn's cards + 2 u = 484 --- (2)

(1) - (2)
7 u - 2 u = 844 - 484
5 u = 360
1 u = 360 ÷ 5 = 72

Number of playing cards that Vaidev had
= 2 u
= 2 x 72
= 144

Number of playing cards that Flynn had
= 484 - 144
= 340

Answer(s): 340