# Question: based on a recent study the monthly utility bills for...

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Based on a recent study, the monthly utility bills for three-room flats in Singapore can be assumed to be normally distributed with mean $135 and standard deviation $42.

If a household living in a three-room flat is randomly selected,

i. What is the probability that its utility bill is more than $155 [3 marks]

ii. What is the probability that its utility bill is between $129 and $165? [4 marks]

iii. If 20% of the utility bills for households living in three-room flats are above a certain value V, find the value of V. [5 marks]