Aperson’s theoretical maximum heart rate (in heartbeats per minute) is 220 - x where x is the person’s age in years (20 ≤ x ≤ 65). when a person exercises, it is recommended that the person strive for a heart rate that is at least 50% of the maximum and at most 75% of the maximum. write a system of linear inequalities that describes the given information.

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

a.

step-by-step explanation:

step 1 distribute 2 to every term in the parentheses

step 2 add 10 on both sides of the equal sign

36 girls

step-by-step explanation:

the 48 boys is 4 parts of the ratio

divide 48 by 4 to obtain one part of the ratio

= 12 ← 1 part of the ratio

3 parts = 3 × 12 = 36 ← number of girls