SOLUTION: Ivory successfully shot 7 of 15 free-throw attempts. How many additional successful free throw, without a miss, must she make in order to attain a success rate of 75%?

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Question 834732: Ivory successfully shot 7 of 15 free-throw attempts. How many additional successful free throw, without a miss, must she make in order to attain a success rate of 75%?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = number of additional free throws needed (without a miss)

(7+x)/(15+x) = 75/100

(7+x)*100 = (15+x)*75

100(7+x) = 75(15+x)

700+100x = 1125+75x

100x-75x = 1125-700

25x = 425

x = 425/25

x = 17

So you need to make 17 free throws in a row to get 75%