A cell phone company orders 600 new phones from a manufacturer. If the
probability of a phone being defective is 3.5%, predict how many of the
phones are likely to be defective. Round to the nearest whole number.

Probability of a defective phone is 3.5%, as a fraction that is 7/200. So it follows:
600 * 7/200 = 4200 / 200 = 21--> Therefore, there is about 21 phones that will be defective.