SOLUTION: Hugo flipped a coin a certain number of times. Hugo flipped tails on 70 percent of the first 50 tosses and on 30 percent of the remaining tosses. If Hugo flipped tails on exactly 5

Question 1044325: Hugo flipped a coin a certain number of times. Hugo flipped tails on 70 percent of the first 50 tosses and on 30 percent of the remaining tosses. If Hugo flipped tails on exactly 50 percent of his total tosses, how many times did he flip the coin.
a)195
b)156
c)127
d)100
e)85

Answer by robertb(5830) (Show Source): You can put this solution on YOUR website!
Let n be the total number of tosses.
Then the number of tails in the first 50 tosses is 0.70*50 = 35.
The number of tails in the remaining n - 50 tosses is 0.30*(n-50).
The total number of tails in the n tosses is 0.50n.
Hence,
35 + 0.30*(n-50) = 0.50n
===> 35 + 0.30n - 15 = 0.50n
===> 20 = 0.20n
===> n = 100, the number of tosses.
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