A study found that 80% of drivers, who ride with a passenger, wear sea

Question

A study found that 80% of drivers, who ride with a passenger, wear seatbelts. Passengers wear seatbelts 70% of the time when the driver wears a seatbelt, and 55% of the time when the driver doesn't wear a seatbelt. What is the probability that a passenger wears a seatbelt?

A. 11%
B. 33%
C. 56%
D. 67%
E. 80%

A. 11%
B. 33%
C. 56%
D. 67%
E. 80%

Sasindran · Answer

D

lets say there are 100 drivers and 100 passengers.

80 driver wear seatbelts and 20 dont.

70% passengers wear seatbelt when the driver wears seatbelt. i.e 80*0.7=56 passengers wear seatbelt

55% passengers wear seatbelt when the driver doesn''t wear seatbelt. i.e 20*0.55=11 passengers wear seatbelt

so on a total 56+11 =67 passengers wear seatbelt. Hence 67%

EgmatQuantExpert · Answer

Solution

https://e-gmat.com/blogs/wp-content/uploads/2018/01/GC_WP.png

Thus, the correct answer is    Option D   .

Regards,
Saquib
Quant Expert
e-GMAT

rahul16singh28 · Answer

Total probability = 0.8(When the Driver wears seat belt)*0.7(When the Passenger wears seat belt) + 0.2(When the Driver doesn't wear seat belt)*0.7(When the Passenger wears seat belt) = 0.67

A study found that 80% of drivers, who ride with a passenger, wear sea

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A study found that 80% of drivers, who ride with a passenger, wear sea

Prep Toolkit

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