A battery manufacturer is interested in thelifetime of its products. Thirty batteries are tested until they fail. The times to failure (in hours) are given below.
41.3 21.1 35.6 13.5 4.2 15.8
5.5 5.8 33.6 18.6 24.3 18.1
3.5 8.4 4211 9.4 10.6 8.9 13.7 19.6 9.2 5.9 19.4 24.2 27.3 30.6 29.4 18.0 32.8 1.1.6
a) The manufacturer claims that 50% of its batteries last longer than 20 h. Describe how your graph shows
whether or not this is true.

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.

At noon a tank contained 10cm water. after several hours it contained 7cm of water. what is the percent decrease of water in the tank?

If the diagram polygon abcd is a reflection across ef to make polygon a'b'c'd'.