BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

probability

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 185
Joined: Thu Feb 04, 2010 3:06 am
Thanked: 6 times

probability

by gmatnmein2010 » Tue Feb 16, 2010 9:25 pm
When a player in a certain game tossed a coin a number of times, 4 more heads than tails resulted. Heads or tails resulted each time the player tossed the coin. How many times did heads result?
1) The player tossed the coin 24 times
2) The player received 3 points each time heads resulted and 1 point each time tails resulted, for a total of 52 points.
Top
Source: — Data Sufficiency |
User avatar
Legendary Member
Posts: 1275
Joined: Thu Sep 21, 2006 11:13 pm
Location: Arabian Sea
Thanked: 125 times
Followed by:2 members

by ajith » Tue Feb 16, 2010 9:33 pm
gmatnmein2010 wrote:When a player in a certain game tossed a coin a number of times, 4 more heads than tails resulted. Heads or tails resulted each time the player tossed the coin. How many times did heads result?
1) The player tossed the coin 24 times
2) The player received 3 points each time heads resulted and 1 point each time tails resulted, for a total of 52 points.
Let H may be the no of times he received heads and T be the number of times he received tails
H -T = 4

1) H+T = 24

Value of H & T can be found out , Sufficient

2) 3H+T =52

4H = 56
H= 14, T=10

[spoiler]Value of H & T can be found out , Sufficient

Hence D[/spoiler]
Always borrow money from a pessimist, he doesn't expect to be paid back.
Top
User avatar
Legendary Member
Posts: 1560
Joined: Tue Nov 17, 2009 2:38 am
Thanked: 137 times
Followed by:5 members

by thephoenix » Tue Feb 16, 2010 9:38 pm
gmatnmein2010 wrote:When a player in a certain game tossed a coin a number of times, 4 more heads than tails resulted. Heads or tails resulted each time the player tossed the coin. How many times did heads result?
1) The player tossed the coin 24 times
2) The player received 3 points each time heads resulted and 1 point each time tails resulted, for a total of 52 points.
IMO D

LET NO. OF TAILS=X----> NO. OF HEADS=X+4.

1:2x+4=24 --> 2x=20 --> x=10 so he tossed the heads x+4--> 14 times.
suff

2: x + 3(x+4)=52 --> 4x+12=52 --> 4x=40 --> x=10 again 14 times is the answer.
suff
Top
User avatar
GMAT Instructor
Posts: 3225
Joined: Tue Jan 08, 2008 2:40 pm
Location: Toronto
Thanked: 1710 times
Followed by:614 members
GMAT Score:800

by Stuart@KaplanGMAT » Wed Feb 17, 2010 12:43 am
gmatnmein2010 wrote:When a player in a certain game tossed a coin a number of times, 4 more heads than tails resulted. Heads or tails resulted each time the player tossed the coin. How many times did heads result?
1) The player tossed the coin 24 times
2) The player received 3 points each time heads resulted and 1 point each time tails resulted, for a total of 52 points.
Let's attack this using the most powerful data sufficiency tool in the known universe: the number of equations vs number of unknowns rule!

Here's the rule:

To solve a system with n variables, one requires n distinct, linear, equations.

From the stem:

2 variables (h, t)
1 equation (4 more heads than tails)

What do we need? 1 more linear equation.

(1) exact sum of heads and tails... that's certainly an equation - sufficient!

(2) 3h + 1t = 52... that's certainly another equation - sufficient!

Each statement is sufficient alone, choose (D).

The better you understand this rule, and the more often you apply it, the fewer actual calculations you'll need to do when solving DS questions.

Remember, in DS we don't care what the answer is, we only care if we can determine the exact answer!
Image

Stuart Kovinsky | Kaplan GMAT Faculty | Toronto

Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course
Top
Post new topic Post Reply
• Page 1 of 1