Question 257571
A baseball players batting average is the ratio of number of hits to number of times at bat. A player has 10 hits out of 20 times at bat. How many consecutive times at bat must a hit be made to raise his average to .600? 

Batting Average = number of hits / number of times at bat.

Right now the batter's average is 10/20.
Let x be the number of consecutive hits needed to raise the average to .600.

Then after x more hits (and also x at bats) the batting average is (10+x)/(20+x)

So we must have:

(10+x)/(20+x) = .600
Solve the above for x:

10+x = .600*(20+x)
10+x = 12 + .6x
.4x = 2
x = 5