The average number of playing cards Pierre and Ahmad had was 476. The average number of playing cards Pierre and Daniel had was 246. If the ratio of Ahmad's playing cards to Daniel's playing cards was 7 : 2, find the number of playing cards Pierre had.
Total number of cards that Pierre and Ahmad had
= 2 x 476
= 952

Total number of cards that Pierre and Daniel had
= 2 x 246
= 492

Number of playing cards Ahmad had = 7 u
Number of playing cards Daniel had = 2 u

Pierre's cards + 7 u = 952 --- (1)
Pierre's cards + 2 u = 492 --- (2)

(1) - (2)
7 u - 2 u = 952 - 492
5 u = 460
1 u = 460 ÷ 5 = 92

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

Number of playing cards that Pierre had
= 492 - 184
= 308

Answer(s): 308