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A professional gambler has won 40% of his 25 poker games for [#permalink]
03 Jun 2012, 10:37

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Difficulty:

25% (medium)

Question Stats:

80% (02:29) correct
20% (01:38) wrong based on 55 sessions

A professional gambler has won 40% of his 25 poker games for the week so far. If, all of a sudden, his luck changes and he begins winning 80% of the time, how many more games must he play to end up winning 60% of all his games for the week?

Re: Percentage problem [#permalink]
03 Jun 2012, 16:57

BDSunDevil wrote:

He needs to win 60% of all the game, i. e. 60% of 25 = 15 He already won 40% of 25 = 10 games. He needs to win 5 more. However his chance is 80%. That is, for every 5 games he play, he win 4. Therefore, he must play (5*5/4)=6.2= 7 more games to win total 15 games. What is the OA?

Re: Percentage problem [#permalink]
03 Jun 2012, 22:54

1

This post received KUDOS

Sorry for the last post.

If he plays X more games, the equation becomes: games with 40% chance + Games with 80% chance = Total games with 60% chance .40*25 + .80*X=.60*(25+X) Solving for X = 25

Re: A professional gambler has won 40% of his 25 poker games for [#permalink]
03 Jun 2012, 23:41

2

This post received KUDOS

Expert's post

farukqmul wrote:

A professional gambler has won 40% of his 25 poker games for the week so far. If, all of a sudden, his luck changes and he began winning 80% of the time, how many more games must he play to end up winning 60% of all his games for the week?

explanation is given in MGMAT book but I didn't understand it...Can anyone please explain?

Re: A professional gambler has won 40% of his 25 poker games for [#permalink]
04 Jun 2012, 01:52

2

This post received KUDOS

Expert's post

farukqmul wrote:

A professional gambler has won 40% of his 25 poker games for the week so far. If, all of a sudden, his luck changes and he began winning 80% of the time, how many more games must he play to end up winning 60% of all his games for the week?

explanation is given in MGMAT book but I didn't understand it...Can anyone please explain?

'The number of games out of which he won 40% games' is equal to 'the number of games out of which he must win 80% of the games'. He won 40% of the games out of 25 games. So he must win 80% of the games out of another 25 games. _________________

Re: Percentage problem [#permalink]
04 Jun 2012, 06:31

davidandcompany wrote:

farukqmul wrote:

A professional gambler has won 40% of his 25 poker games for the week so far.If,all of a sudden,his luck changes and he began winning 80% of the time,how many more games must he play to end up winning 60% of all his games for the week?

explanation is given in MGMAT book but I didn't understand it...Can anyone please explain?

Let x = number of games more must he play

0.4(25) + 0.8x = 0.6(25+x) <--- You should be able to grasp this idea.

Re: Percentage problem [#permalink]
04 Jun 2012, 06:33

Expert's post

farukqmul wrote:

davidandcompany wrote:

farukqmul wrote:

A professional gambler has won 40% of his 25 poker games for the week so far.If,all of a sudden,his luck changes and he began winning 80% of the time,how many more games must he play to end up winning 60% of all his games for the week?

explanation is given in MGMAT book but I didn't understand it...Can anyone please explain?

Let x = number of games more must he play

0.4(25) + 0.8x = 0.6(25+x) <--- You should be able to grasp this idea.