Question

W varies jointly as x and p. If W = 78 when x = 2 and p =10, find x when W = 858 and p =5.5.

Answer 1

The formula here is W = xpk, where k is the constant. If you fill in the values you are given, then 78=(2)(10)k. Find k to solve the next thing they are asking you for, which is to find x when you are given W and p. Like this:\[78=20k\]and k = 3.9 Now use that 3.9 to find x in your equation.\[W = xpk->358=x(3.9)(5.5)\]

Answer 2

solving for x you get \[x=\frac{ 358 }{ 3.9*5.5 }\]and x = 16.69