Question

If y varies directly with x, and y =9 when x=3, what is x when y=15

Answer 1

directly varies for that mean if y increases x will increase too and the other way around if y decreases x will decrease too.

an easy way to solve this is to make all values into fraction ik it sounds confusing lemme explain it. so if we say
`(x)/(y)` and add the values of the known
`(3)/(9)` we can say that if
`(x)/(15)` is equal to
`(3)/(9)`

now we just solve it for x

`(x)/(15) = (3)/(9) \\9x = 45\\x= 5`

hence when y is 15 x will be 5