# Probability

Ravi asked his neighbor to water a delicate plant while he is away.Without water, the plant would die with probability 4/5 and with water it would die with probability 3/20. The probability that Ravi’s neighbor would remember to water the plant is 9/10. If the plant actually died, what is the probability that Ravi’s neighbor forgot to water the plant?

(A) 4/5 (B) 27/43 (C) 16/43 (D) 2/25

Note by Kushal Bose
1 year, 8 months ago

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C

- 1 year, 8 months ago

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- 1 year, 8 months ago

P(waterless death | death).
= ((4/5)(1-9/10)) / ((4/5)(1-9/10)+(3/20)(9/10)).
= (4/50) / (4/50+27/200).
= 16/43 (C)

- 1 year, 8 months ago