The bananas are not an equal number so you would not have the same amount unless you take one out.
From 100 to 80 is 8/10, so the recursive formula is
an=a(n-1)*1/8
or
an= a1*1/8(n-1)
an=a1*(n-1)/8
The answer is 29.5
Okkkkkkkkrrrrrrrr It is a long division just use calculator
$21.22
Multiply 19.74 times 0.075 (7.5% converted to a decimal) to get 1.48 (the amount of tax) and add that to the cost of the meal (19.74)