Question

1. z varies jointly with x and y.

when x = 2 and y = 3, z = 60.
what is the value of z when x = 4 and y = 9?
○ 40
○ 60
○ 90
○ 360

Explanation:

Step1: Define joint variation formula

$z = kxy$ (k is constant)

Step2: Calculate k with given values

$60 = k(2)(3) \implies 6k = 60 \implies k = 10$

Step3: Compute z for x=4,y=9

$z = 10(4)(9) = 360$

Answer:

360