The original price was $22.5.
18 divided by 0.8 is 22.5.
If you double check 22.5 times 0.8, you will get 18, your sales price.
Answer: 44 boys and 40 girls
Step-by-step explanation:
x = number of girls
x + 4 = number of boys
x + x + 4 = 84
2x + 4 = 84
2x = 80
x = 40
84 - 40 = 44