Chapter 1.2, Problem 38ES

Projecting Birth Weight. Ultrasonic images of 29-week-old fetuses can be used to predict birth weight. One model, or formula, developed by Thurnau, is $P=9.337da-299$ a second model, developed by Weiner, is $P=94.593c+34.227a-2134.616$. For the formulas, P is the estimated birth weight, in grams, d is the diameter of the fetal head, in centimeters, c is the circumference of the fetal head, in centimeters, and a is the circumference of the fetal abdomen, in centimeters.

Full-Time-Equivalent Students. Colleges accommodate students who need to take different total-credit-hour loads. They determine the number of “full-time-equivalent” students, F, using the formula

$F=\frac{n}{15}$,

where n is the total number of credits students enroll in for a given semester.

a. Determine the number of full-time-equivalent students on a campus in which students register for 42,690 credits.

b. Solve the formula for n.