The target heart rate is the heartbeat rate during aerobic exercise that provides a benefit to your heart. The target heart rate for a person exercising at 70% intensity is given by the equation y = 0.7(200 - x) where y is the target heart rate in beats per minute and x is the person’s age in years.
How old is a person with a target heart rate of 133 beats per minute?
How old is a person with a target heart rate of 126 beats per minute?

Write the converse of the following statement: if the trees have no leaves, then it is fall. if the trees have no leaves, then it is fall. the trees have no leaves, therefore it is fall. it is fall since the trees have no leaves. if it is fall, then the trees have no leaves.

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.

Varies inversely with x. if y=8.5 when x=-1 find x when y=-1