Question 1161415
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It's not clear what "probability of sales on three calls" means.<br>
I interpreted it as a single sale, with no sale on either of the first two calls but a sale on the third call.<br>
P(no sale on first call) = 1-0.7 = 0.3
P(no sale on second call) = 1-0.1 = 0.9
P(sale on third call) = 0.1<br>
P(first sale on third call) = (0.3)(0.9)(0.1) = 0.027 = 2.7%<br>