Marsha burns 9 cal per minute on the treadmill and 7 cal per minute on the elliptical. If she spent a total of 57 minutes working out and burn a total of 463 cal, how many minutes did she spend on the elliptical?

step-by-step explanation:

given that ab is divided into equal parts as

ac, cd, de, ef, fg, gh, hi, ib.

from this we find that f is the midpoint of ab.

so using mid point formula we find

f = (3,7)

similarly considering fb, we get

h = mid point of fb = ((6,6) and g, mid point of fh is

g = (9/2, 13/2)

i is mid point of hb

so i =(15/2,11/2)

i can answer this if i have the answer choices