I cannot seem to get the right answer.

Question

Animal Pulse Rate According to one model, an animal’s heart rate varies according to its weight. The formula N(w)=885w^-1/2 gives an estimate for the
average number N of beats per minute for an animal that weighs w pounds. Use the formula to estimate the heart rate for a horse that weighs 800 pounds. To be brutally honest I cannot get this right at all.

Answer 1

I assume that you know that w^-1/2 means the square root of w in the denominator.

N = 885/sqrt(800) = 31.3 beats/minute

This must be a resting heart rate.