A gambler has won 40% of his 40 poker games for the week so far. If, all of a sudden, his luck changes and he begins winning 70% of the time, how many more games must he play to end up winning 60% of all his games for the week?
Select the correct option
A) 50  B) 60  C) 70  D) 80  E) 90
Let x be the number of additional games the gambler needs to play.   0.4(40) + 0.7x = 0.6(x+40)   0.1x = 8   x = 80   The answer is 80.
<result>D</result>
A gambler has won 40% of his 40 poker games for the week so far. If, all of a sudden, his luck changes and he begins winning 70% of the time, how many more games must he play to end up winning 60% of all his games for the week?