Question

A person's systolic blood pressure, which is measured in millimeters of mercury (mm Hg), depends on a person's age, in years.

Answer 1

Answer:

(A)The systolic pressure of a person of age 44 is 135.1 mm Hg

(B) If a person's systolic pressure is 133.36 mm Hg, their age is 41 years.

Step-by-step explanation:

Given : P = 0.007 y² - 0.01 y +122

where P is systolic pressure and y is age of a person

(A) Here age of the person, y =44

So, P =0.007 (44²) -0.01 (44) +122 = 13.552 -0.44 +122 = 135.112 =135.1 mm

∴ The systolic pressure of a person of age 44 is 135.1 mm Hg

(B) Here P = 133.36 mm Hg

So,

133.36 = 0.007 y² - 0.01 y +122

=>0.007 y² -0.01 y -11.36 =0

=> 7 y² -10 y -11360 =0

Solving the above quadratic equation using quadratic formula, we have

$y = \frac{5+\sqrt{79545} }{7}$

or $y = \frac{5-\sqrt{79545} }{7}$

y = 41 or y = -39.57

Since age cannot be negative, y= 41

∴ If a person's systolic pressure is 133.36 mm Hg, their age is 41 years.