Answer:
$42.80 check
x.20 tip
$8.56
Then add the the total check $42.80 +$8.56 = $51.36 John will spend
Explanation:
to find the tip multiply the total by the tip
if 10% x it by .10
if 16% x it by .16
if 25 % x it by.25 and so on then add that to the total of the bill