問唔識題目ar!!

1. $2 x 3 + $5 x 18
2. $2 x 8 + $5 x 16
3. $2 x 13 + $5 x 14
4. $2 x 18 + $5 x 12
There are only four ways.
Step by Step
1. A boy only can pay $ 2 coin for $6 from $96
1a. For remaining $90, a boy can pay all $5 for $90 (18pcs)
2-4. For replacing the 2 x $5 = $10, a boy can pay $2 x 5 = $10 instead.
Since a boy only have 17 pcs left (3pcs for $6 payment), there are 3
more additional different ways.
The answer are 4 ways.