Mrs Brandon had a sum of money. If she bought 5 chocolate bars and 6 mini cupcakes, she would have $50 left. If she bought 2 chocolate bars and 8 mini cupcakes, she would have $51 left. Given that she had $89, how many chocolate bars could she buy at most?
Cost of 1 chocolate bar = 1 C
Cost of 1 mini cupcake = 1 M

5 C + 6 M + 50 = 89
5 C + 6 M = 89 - 50
5 C + 6 M = 39 ---- (1)

2 C + 8 M + 51 = 89
2 C + 8 M = 89 - 51 
2 C + 8 M = 38 ---- (2)

Make M the same.

(1) _{x 4}
20 C + 24 M = 156 ---- (3)

(2) _{x 3}
6 C + 24 M = 114 ---- (4)

(3) - (4) 
20 C - 6 C = 156 - 114
14 C = 42

1 C = 42 ÷ 14 = 3

Number of chocolate bars that Mrs Brandon can buy
= 89 ÷ 3
= 29 r 2

Most number of chocolate bars that Mrs Brandon can buy = 29

Answer(s): 29