Z varies inversely as the cube of d. If z = 3 when d = 2, how do you find z when d is 4?

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Answer 1 · 2017-06-01T06:24:00

#z=3/8#

#z# varies inversely as the cube of #d# means #zprop1/d^3#

In other words #z=kxx1/d^3#, where#k# is a constant.

Now as #z = 3# when #d = 2# means

#3=kxx1/2^3# or #3=kxx1/8# or #k=8xx3=24#

Hence #z=24xx1/d^3=24/d^3#

Therefore when #d=4#,

#z=24xx1/4^3=24/64=3/8#.