Question

When exercising, a person's pulse rate should not exceed a certain limit, which depends on his or her own age. this maximum rate is represented by the expression 0.8(220-a), where a is age in years. find the age of a person whose maximum pulse is 152?

Answer 1

The person is 30 years old! Here's how you solve it:

A = .8 (220-a) 
152 = .8 (220-a) 
152 = 176 - .8a 
.8a = 24 
a = 30 

Hope this helps!