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

Ali's heart rate is 135 beats per minute

Explanation:

Let

x ----> Ali's heart rate

y ----> Ben's heart rate

we know that

`(x)/(y)=(15)/(17)`

isolate the variable x

`x=(15)/(17)y` ----> equation A

we have

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

Solve the system by substitution

substitute equation B in equation A

`x=(15)/(17)(x+18)`

Solve for x

`x-(15)/(17)x=(15)/(17)(18)`

`(2)/(17)x=(270)/(17)`

simplify

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

therefore

Ali's heart rate is 135 beats per minute