I need help what is this ??? if t varies inversely as the cube of Z and directly as the square of r and t =4 when z=3 and r=6 find t when z =6 and r =9

Question

840 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-05-19T03:57:40

Solution: # t= 1.125#

#t prop 1/z^3 and t prop r^2# , so by joint variation,

#t prop r^2/z^3 or t = k* r^2/z^3 ; k # is constant of variation.

#t = k* r^2/z^3 ; t=4#, when # z=3 and r=6 #

#4 = k* 6^2/3^3 :. k = 4 *27/36 or k=3#.Hence the variation

equation becomes #t = 3 * r^2/z^3 ; z=6 , r= 9, t = ?#

#:. t = 3 * 9^2/6^3= 3*81/216 =81/72=9/8=1.125#

Solution: # t= 1.125# [Ans]