Let f(x) represents the heart beat of the person.
Now, we have been given that person’s theoretical maximum heart rate is given by 220 - x.
Also, we have been given that person strive for a heart rate that is at least 50% of the maximum. At least means greater than equal to.
Thus, we have

Also, we have been given that person strive for a heart rate that is at most 75% of the maximum. At most means less than equal to.
Therefore, the system of inequality is given by

Replace every n with 15 to get 15*(15-1)/2 = 15*14/2 = 15*7 = 105
Answer is choice C
8 is the only input value listed in the answers.
Answer:
Two ratios equivalent to 27:9
A) 3:1
B)9:3
Answer:
45°
Step-by-step explanation:
the sum of angles in a triangle is equal 180°
we have been given that one angle equals yo 90° and the other equals to 45°
let "?" be the unknown angle
====> 180° = 90° + 45° +?
? = 180° - (90° + 45°)
? = 180° - 135°
? = 45°