Question

If y varies directly with x and y = 16 when x = 4, find x when y = 8.

Answer 1

Answer: X = 2

Step-by-step explanation:

Y & X

Y = KX

K = Y/X = 16/4 = 4

Y= 8

K =4

X=?

X = Y/K

X = 8/4 = 2

Answer 2

Step-by-step explanation:

$Given: \\ y \: \alpha \: x \\ \therefore \: y = kx..(k = constant)..(1) \\ \\ let \: us \: substitute \: x = 4 \: and \: y = 16 \: \\ in \: equation \: (1)\\ \\ 16 = 4k \: \\ \implies \: k = \frac{16}{4} \\ \implies \: k = 4 \\ substituting \: k = 4 \: in \: equation \: \\ (1) \: we \: find : \\ y = 4x....(2) \\ now \: we \: need \: to \: find \: x \: when \: y = 8 \\ \therefore \: 8 = 4x \\ \implies \: x = \frac{8}{4} \\ \huge \orange{ \boxed{\implies \: x = 2}}$