M is partly constant and partly varies with N, when N= 14, M = 150 and when N = 54, M = 192.

Find the formula connecting M and N
hence find M when N= 73
m=k+cn
192=k+54c............................. (1)
150=k+14c. ........................... (2)
subtract (1) from (2)
142=40c
divide both sides by 40
142÷40=40c÷40
c=3.55
put 3.55 for c in (1)
192=k+54×3.55
192=k+191.7
k=192 - 191.7
k=0.3
m=k+cn
m=0.3+3.55×73
m=0.3+259.15
m=259.45

192=k+54c............................. (1)

150=k+14c. ........................... (2)
subtract (1) from (2)
142=40c
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whoops
42 not 142