GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 21 Sep 2018, 16:55

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

A soccer player has 80% chance of scoring a goal at his penalty kicks.

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Intern
Intern
avatar
Joined: 20 Aug 2018
Posts: 2
A soccer player has 80% chance of scoring a goal at his penalty kicks.  [#permalink]

Show Tags

New post Updated on: 20 Aug 2018, 19:54
2
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

78% (01:29) correct 22% (01:18) wrong based on 41 sessions

HideShow timer Statistics

A soccer player has 80% chance of scoring a goal at his penalty kicks. What is the probability that he is going to miss at least a goal in two penalty kicks?

(A) 0
(B) 16/25
(C) 12/25
(D) 9/25
(E) 1/25

Originally posted by rafaellareale on 20 Aug 2018, 17:46.
Last edited by Bunuel on 20 Aug 2018, 19:54, edited 1 time in total.
Renamed the topic, added the OA and moved to PS forum.
Intern
Intern
avatar
S
Joined: 12 Oct 2017
Posts: 40
Re: A soccer player has 80% chance of scoring a goal at his penalty kicks.  [#permalink]

Show Tags

New post 20 Aug 2018, 20:30
1
The probability that he is going to miss at least a goal in two penalty kicks = 1 - The probability that he has 2 goals
= 1-0.8x0.8 = 9/25.

Hence, the answer is D.
Senior SC Moderator
avatar
V
Joined: 22 May 2016
Posts: 1978
Premium Member CAT Tests
A soccer player has 80% chance of scoring a goal at his penalty kicks.  [#permalink]

Show Tags

New post 20 Aug 2018, 22:21
1
rafaellareale wrote:
A soccer player has 80% chance of scoring a goal at his penalty kicks. What is the probability that he is going to miss at least a goal in two penalty kicks?

(A) 0
(B) 16/25
(C) 12/25
(D) 9/25
(E) 1/25

This question has us thinking in negatives.

Probability of missing at least "a" goal (at least ONE goal)? Use the complement rule.

Here: the negation or opposite of “at least one” is “none." That is,

P (at least one miss) = 1 - P(no misses)

P of "no misses"?
If he misses NONE, he makes BOTH
+Goal +Goal
No misses

P(no misses) = 1 - P(making both goals)*

P(making both goals): \((\frac{8}{10}*\frac{8}{10})=\frac{64}{100}\)

P(no misses):
\((1-\frac{64}{100})=\frac{36}{100}=\frac{9}{25}\)

P(missing at least one goal)= \(\frac{9}{25}\)

Answer D

*Because
P(making both goals) + P(missing both goals) = 1

P(missing both goals) = 1 - P(making both goals)

_________________

In the depths of winter, I finally learned
that within me there lay an invincible summer.

-- Albert Camus, "Return to Tipasa"

BSchool Forum Moderator
User avatar
V
Joined: 26 Feb 2016
Posts: 3136
Location: India
GPA: 3.12
Premium Member CAT Tests
A soccer player has 80% chance of scoring a goal at his penalty kicks.  [#permalink]

Show Tags

New post 20 Aug 2018, 22:31
1
1
rafaellareale wrote:
A soccer player has 80% chance of scoring a goal at his penalty kicks. What is the probability that he is going to miss at least a goal in two penalty kicks?

(A) 0
(B) 16/25
(C) 12/25
(D) 9/25
(E) 1/25


There are 2 penalty kicks that the soccer player will take.

The probability of scoring a goal is 80% or \(\frac{4}{5}\). The probability of not scoring a goal is \(1 - \frac{4}{5} = \frac{1}{5}\)

There are 3 possibilities where he is going to miss at least one goal
1. When the soccer player misses the first goal and scores the second goal = \(\frac{1}{5}*\frac{4}{5} = \frac{4}{25}\)
2. When the soccer player scores the first goal and misses the second goal = \(\frac{4}{5}*\frac{1}{5} = \frac{4}{25}\)
3. When the soccer player misses both goals = \(\frac{1}{5}*\frac{1}{5} = \frac{1}{25}\)

Therefore, the total probability that the soccer player misses at least one goal is \(\frac{4}{25} + \frac{4}{25} + \frac{1}{25} = \frac{9}{25}\)(Option D)
_________________

You've got what it takes, but it will take everything you've got

Senior Manager
Senior Manager
User avatar
P
Joined: 22 Feb 2018
Posts: 324
Re: A soccer player has 80% chance of scoring a goal at his penalty kicks.  [#permalink]

Show Tags

New post 21 Aug 2018, 01:56
rafaellareale wrote:
A soccer player has 80% chance of scoring a goal at his penalty kicks. What is the probability that he is going to miss at least a goal in two penalty kicks?

(A) 0
(B) 16/25
(C) 12/25
(D) 9/25
(E) 1/25


OA:D
the probability that he is going to miss at least a goal in two penalty kicks = 1 - the probability that he scores both of the goals

probability that he scores both of the goals \(=\frac{80}{100}*\frac{80}{100}=\frac{4}{5}*\frac{4}{5}=\frac{4}{5}*\frac{4}{5}=\frac{16}{25}\)

the probability that he is going to miss at least a goal in two penalty kicks\(= 1 - \frac{16}{25}=\frac{9}{25}\)
_________________

Good, good Let the kudos flow through you

Director
Director
User avatar
G
Joined: 20 Feb 2015
Posts: 733
Concentration: Strategy, General Management
Premium Member CAT Tests
Re: A soccer player has 80% chance of scoring a goal at his penalty kicks.  [#permalink]

Show Tags

New post 21 Aug 2018, 02:56
rafaellareale wrote:
A soccer player has 80% chance of scoring a goal at his penalty kicks. What is the probability that he is going to miss at least a goal in two penalty kicks?

(A) 0
(B) 16/25
(C) 12/25
(D) 9/25
(E) 1/25



no of ways he can score 1 out of 2 = 2 ways
no of ways he misses both = 1 way

p(missing at least 1 goal) = 2*(he scores one) + 1*(he misses both)
= 2*4/25 + 1/25 =9/25

another way--

p(missing at least 1) = 1-p(scoring both)
=1-(4/25 *4/25)
=1-16/25
=9/25
Re: A soccer player has 80% chance of scoring a goal at his penalty kicks. &nbs [#permalink] 21 Aug 2018, 02:56
Display posts from previous: Sort by

A soccer player has 80% chance of scoring a goal at his penalty kicks.

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

Events & Promotions

PREV
NEXT


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.