Can someone explain how to figure this

a cell phone company orders 500 new phones from a manufacturer. if the probability of a phone being defective is 2.9%, predict how many of the phones are likely to be defective. round to the nearest whole number.

2.9% OF the 500 phones are more than likely defective. In order to figure this out you must do 500*0.029 which would equal 14.5 and rounds off to 15. 15 out of the 500 phones will maybe be defective.

So the first thing we do is to multiply the top equation by 3. the reason i want to do this is i notice there will be a 6y on both equations and can possibly add/subtract them. so we get 6y = -3x + 27. adding that and the second equation we get 6x = 27-15 which is 12. divide by 6 and we get 2. ∴ x = 2. substituting 2 into the first equation we get 2y = -2 + 9 which is 7. divide by 2 and we get 7/2. ∴ y = 7/2, x = 2.

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