The average number of stickers that Bryan and Charlie have is 39.
The average number of stickers that Bryan and Adam have is 49.
The number of stickers that Charlie has is ⁵₉ as many as Adam.

1. How many stickers does Bryan have?
2. How many stickers does Charlie have?
3. How many stickers does Adam have?

(a)
Number of stickers that Bryan and Charlie has
= 2 x 39
= 78

Number of stickers that Bryan and Adam has
= 2 x 49
= 98

Number of stickers that Charlie has = 5 u
Number of stickers that Adam has = 9 u

Let the number of Bryan's stickers be B.
Let the number of Charlie's stickers be C.
Let the number of Adam's stickers be A.


B + C = 78
B + 5 u = 78 --- (1)

B + A = 98
B + 9 u = 98 --- (2)

(2) - (1)
(B + 9 u) - (B + 5 u ) = 98 - 78
B + 9 u - B - 5 u = 20
B - B + 9 u - 5 u = 20

4 u = 20

1 u = 20 ÷ 4 = 5

Substitute 1 u = 5 into (1).
B + 5 x 5 = 78
B + 25 = 78
B = 78 - 25 = 53

Number of stickers that Bryan has = 53

(b)
Number of stickers that Charlie has
= 5 u
= 5 x 5
= 25

(c)
Number of stickers that Adam has
= 9 u
= 9 x 5
= 45

Answer(s): (a) 53; (b) 25; (c) 45