Question

Ali and Ben measured their heart rates. The
ratio of their heart rates was 15:17. Ben's
heart beat 18 beats per minute more than
Ali's. Calculate Ali's heart rate.​

Answer 1

Answer:

Ali's heart rate is 135 beats per minute

Step-by-step explanation:

Let

x ---->  Ali's heart rate

y ----> Ben's  heart rate

we know that

$\frac{x}{y}=\frac{15}{17}$

isolate the variable x

$x=\frac{15}{17}y$ ----> equation A

we have

$y=x+18$ ---> equation B

Solve the system by substitution

substitute equation B in equation A

$x=\frac{15}{17}(x+18)$

Solve for x

$x-\frac{15}{17}x=\frac{15}{17}(18)$

$\frac{2}{17}x=\frac{270}{17}$

simplify

$2x=270\\x=135\ beats\ per\ minute$

therefore

Ali's heart rate is 135 beats per minute