Answer:
Ali's heart rate is 135 times per minute.
Step-by-step explanation:
Let Ali's heart rate be denoted by x times per minute.
It is provided that Ben's heart beats 18 times per minute more than Ali.
The ratio of their heart rates was 15:17.
That is:
[tex]\frac{15}{17}=\frac{x}{x+18}[/tex]
Solve for x as follows:
[tex]\frac{15}{17}=\frac{x}{x+18}[/tex]
[tex]15(x+18)=17x\\15x+270=17x\\2x=270\\x=135[/tex]
Thus, Ali's heart rate is 135 times per minute.