Question

m varies jointly as q and r. One set of values is m = 86.4, q = 9, and r = 12. Find m when q = 20 and r = 6.5.

Answer 1

M=kqr
k=constant of propoertionality

86.4=k(9)(12)
86.4=108k
divide both sides by 108
86.4/108=k

M=(86.4/108)qr

q=20
r=6.5
M=(86.4/108)(20)(6.5)
M=104