In a certain party, every person drinks either tea or coffee. If 60%

Question

In a certain party, every person drinks either tea or coffee. If 60% drink tea and 70% drink coffee, what is the probability that a person drinking tea also drinks coffee?

A. 1/2
B. 1/6
C. 1
D. 3/10
E. 21/50

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Ashokvardhan · Accepted Answer

The question is about the probability of people drinking tea and also coffee
drinking tea = 60 
both = 30
probability = 30/60 =1/2
hence A
At first even I marked D but reading the question thrice helped me to get the logic

bacca2323 · Answer

Total = 100
C = Coffee = 70
T = Tea = 60
Neither Tea nor Coffee = 0 (the text says so) 
100 = 60 + 70 + 0 - x
x = 30 (people who drink both Tea and Coffee) 
So the chance is 30/100 that is 3/10. 
Hence Number D imo.

Kinshook · Answer

In a certain party, every person drinks either tea or coffee. If 60% drink tea and 70% drink coffee, what is the probability that a person drinking tea also drinks coffee?

Drinks Tea 
 ~Drinks Tea 
 Total 
 
  Drinks Coffee 
 30% 
 40% 
 70% 
 
  ~Drinks Coffee 
 30% 
 0% 
 30% 
 
  Total 
 60% 
 40% 
 100%

The probability that a person drinking tea also drinks coffee = 30%/60% = 1/2

IMO A

onlymalapink · Answer

i d9nr understand the probabilty done in the end it doesnt make sense ro me30/60 why

hr1212 · Answer

Conditional probability P(A/B) =  \frac{P(A ∩ B)}{P(B)}  ie. probability of event A such that event B occurs

Here, P(Coffee/Tea) =  \frac{P({Coffee ∩ Tea})}{P(Tea)} , where,

P(Coffee ∩ Tea) = 30/100 = 3/10 
 P(Tea) = 60/100 = 6/10

which means, P(Coffee/Tea) =  \frac{3/10}{6/10}  =  \frac{1}{2}

Answer : A

In a certain party, every person drinks either tea or coffee. If 60%

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	Drinks Tea	~Drinks Tea	Total
Drinks Coffee	30%	40%	70%
~Drinks Coffee	30%	0%	30%
Total	60%	40%	100%

GMAT Problem Solving (PS) Questions

In a certain party, every person drinks either tea or coffee. If 60%

Prep Toolkit

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