I have a worksheet where I need to figure out how many more responses I will need to obtain the desired score (percentage).

I have seven columns:
a) "x number" of responses earning 100% score
b) "x number" of responses earning 75% score
c) "x number" of responses earning 50% score
d) "x number" of responses earning 0% score
e) total number of responses
f) average percentage of all responses

g) Desired score


The idea is to manually input the desired percentage in column G. Then I would like it to calculate the amount of 100% responses (column A) that are needed to achieve that desired percentage.

Thanks for any input you may have.