P varies directly as q and inversely as y. One set of values is P = 0.064, q = 16 and y = 5. Find P when q = 12 and y = 10.

Y varies inversely as x means y=kx

y varies directly as x means y=k/x

p varies directly as q and inversely as y

p = (qk) / y

0.064 = (16k) / 5

find k

times both sides by 5

0.32=16k

divide both sides by 16

0.02=k

p = (0.02q) / y

q=12

y=10

p = (0.02*12) / 10

p = (0.24) / 10

p=0.024