Probability of cancer because of microwaves

[arkan]

Please help understand how to solve this question. Sorry for the terrible English.

If there’s 10% chance of getting cancer from microwaves, and 3% of the population gets cancer, what is the probability that a certain person who have cancer and was exposed to microwaves got it as a result from his exposure, if 15% of the population are exposed to microwaves.

 

[HallsofIvy]

Imagine a population of 100000 people. "15% of people use microwaves": 15000 people use microwaves. "

If there’s 10% chance of getting cancer from microwaves" then 10% of 15000= 1500 of those people get cancer from microwaves. "

3% of the population gets cancer". That is 3% of 100000= 3000 people who get cancer.

Of the 3000 people who get cancer, 1500, 50% or them, get it from microwaves.

(I don't believe any of these numbers, by the way.)

(Your English is excellent. Much better than my [insert whatever language you like here. Maybe even English!)])
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