The half-life of carbon-11 is 20 min. a sample of carbon-11 has 25 mci. how many half-lives of carbon-11 occur in 1 hour? how much carbon-11 is in the sample 1 hour after the original sample is measured? a. 3 half-lives; 0.313 mci b. 4 half-lives; 1.563 mci c. 3 half-lives; 3.125 mci d. 4 half-lives; 23 mci

Which of the following statements is not true? a. parallel lines are lines in the same plane that never intersect. b. congruent figures have the same shape and same size angles and sides. c. similar figures must have the same shape and the same size. d. a rotation is when you turn a figure around a certain point.

Aswimming pool measures 22ft by 12ft and is 4ft deep. if the pool is being filled at 2.5 cubic ft per minute, how long will it take to fill the pool?

Acompany produces packets of soap powder labeled “giant size 32 ounces.” the actual weight of soap powder in such a box has a normal distribution with a mean of 33 oz and a standard deviation of 0.7 oz. to avoid having dissatisfied customers, the company says a box of soap is considered underweight if it weighs less than 32 oz. to avoid losing money, it labels the top 5% (the heaviest 5%) overweight. how heavy does a box have to be for it to be labeled overweight?