URGENT! YOU CAN ALSO LOOK AT THE PIC. PLZ. The target heart rate is the heartbeat rate during aerobics 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. . a) How old is a person with a target heart rate of 133 beats per minute? b) What is the target heart rate of a 20-year-old person?