Question 141620
The ideal maximum heart rate for 25 years old who burn fat is 117 beats per minute. For every 5 years older than 25, that ideal rate drops 3 beats per minute. Write a linear equation to find the ideal maximum over 25 who is exercising to burn fat. Graph the equation. Find the ideal maximum heart rate for a person exercising to burn fat who is 55 years old.
:
Assign the given values as follows
x1 = 25; y1 = 117

:
-3 beats for every 5 yrs, we know the slope will be {{{-3/5}}}
:
Find the equation using the point/slope formula
y - 117 = -{{{3/5}}}(x - 25)
y - 117 = -{{{3/5}}}x + 15
y = -{{{3/5}}}x + 15 + 117
y = -{{{3/5}}}x + 132
:
Graph this:
{{{ graph( 300, 200, -20, 120, -50, 180, -.6x+132) }}}
:
"Find the ideal maximum heart rate for a person exercising to burn fat who is 55 years old."
Substitute 55 for x and find y in the above equation
y = -{{{3/5}}}(55) + 132
y = -33 + 132
Y = 99 bbm for a 55 yr old