Latest Gmate Aptitude Question SOLUTION: A shopkeeper has 13 washing machines out of which 5 are defective. A customer buys 3 washing machine. What is the probability that exactly one machine is defective? (a) 1/20 (b) 1

• Placement Papers
• /
• Gmate
• /
• Category

Gmate Question Papers:

(#M40164894) GMATE Category question Keep an EYE

A shopkeeper has 13 washing machines out of which 5 are defective. A customer buys 3 washing machine. What is the probability that exactly one machine is defective?
(a) 1/20 (b) 1/5 (c) 70/143 (d) 35/143

Asked In Gmate taasha (3 years ago)

Unsolved Read Solution (4)

Is this Puzzle helpful?   (20)   (7) Submit Your Solution

Read Solution (4) :

Boinibal Sreelatha  (3 years ago)

5 are defective and (13-5) are not defective so out of 3 machines 1 from defective and 2 from not defective.
(5C1x8C2)/13C3 = 70/143

Is this solution Helpfull? Yes (2) | No (1)  

Divya Batra  (3 years ago)

answer is (c) 70/143
explanation:-
total=13
defective=5
not defective=8
so, he bought 3 machines, out of which 1 must be defective and 2 be non-defective.
so, he must bought 2 from 8(non-defective machines) and 1 from 5(defective machines).
so, answer is:-
(8 C 2 * 5 C 1) / 13 C 3 =70/143 is the answer.

Is this solution Helpfull? Yes | No   

Divya Batra  (3 years ago)

sorry, answer is (d)35/143
it was my calculation mistake.

Is this solution Helpfull? Yes | No   

srishti  (1 year ago)

8C2*5C1 / 13C3 = 70/143

Is this solution Helpfull? Yes | No   

Please Login to Read Solution.