Answer:
Dave paid $4.20 more than Mel
Explanation:
Lets start with Dave:
Turn the % into a decimal - so 7.5 % would be 0.075
Then multiply it to the amount in cost to get the tax - 24 x 0.075 = 1. 80
Now add the tax to the total - 24 + 1.8 = $25. 80
Mel
Turn the % into a decimal - so 8 % would be 0.08
Then multiply it to the amount in cost to get the tax - 20 x 0.08 = 1. 60
Now add the tax to the total - 20 + 1.6 = $21.60
To find the difference subtract Dave's with Mel's
$25. 80 - $21.60 = $4.20