Anthony T. answered • 05/19/21
Effective Math Tutor specializing in Algebra and logical thinking.
Hi Berezka, when we're looking to find the probability of more than one event, we multiply the individual probabilities. The question tells us that the probability that the sale will be profitable is 0.3 for each store. We can first rewrite the 0.3 as a fraction, which would be 1/3. The probability of turning a profit in one store is 1/3, so to find the probability to turning a profit in 2 stores, you multiply that probability twice. So it would be 1/3 times 1/3, which would give you 1/9. Your answer is 1/9. Notice that 1/9 is actually a much smaller number than 1/3. This makes sense, because the more events you want to test the probability of happening together, the less likely ALL of them will happen at once. Think of it this way: Your probabibilty of winning the lottery is already incredibly low, so of course your probability of winning the lottery twice in a row is even lower. This is the exact scenario in this question. You're trying to see if an event will happen not just once, but at least TWICE in a row, so of course the probability will be even lower. I hope this helped!
