Question

Two quantities, x and y, are directly proportional. If x is tripled, what happens to y? It is multiplied by 13. It is tripled. It is multiplied by 9. It depends on the starting value of x.

Answer 1

Answer: It is tripled.

Since x and y are proportional, whatever happens to x must happen to y in order for the two values to stay proportional.

Answer 2

Option B.

Explanation:

It is given that two quantities, x and y, are directly proportional. It means

`y\propto x`

`y=kx`

where, k is constant of proportionality.

We need to find the effect on y if x is tripled.

Let
`x_1=3x`, then

`y_1=k(3x)`

`y_1=3(kx)`

`y_1=3y`

It means y is also tripled.

Therefore, the correct option is B.