Answer:
Your heart rate would be 72 beats per minute
Step-by-step explanation:
You need to get 60 minutes so If you multiply 15 by 4, its 60. Do the same for 18 and your heart rate is 72 beats per minute
To solve this problem we must know that when any two lines intersect , a pair of opposite angles from the figure Will be equal
so that means that

we can subtract twenty from each side


now we can subtract like terms

so we can get the final answer as
0.77777777777777 and goes on forever since anything/9 is 0.(whatever that number is repeated)