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

Answer:

Option B.

Step-by-step 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.