Question

P varies partly as the cube of M and partly as the inverse of M.if M=2 when P=1and M=6,when P=4, write out an expression for P. Hence find P when M=7

Answer 1

p = k m^3 + j /m

1 = 8 k + j/2
4 = 216 k + j/6

1 = 8 k + j/2
12 = 648 k + j/2
--------------------------- subtract
-11 = - 640 k
k = .0172
j = 1.725
p = 0.0172 m^3 + 1.725/m