Variation Functions-1

Question

If y varies directly as x, and y = 24 when x = 15, then find y when x = 3. Just type the number. If the answer is not an integer, then write it as a fraction in simplest form, with a slash (/) between the numerator and the denominator.

Answer 1

If to numbers are directly proportional they are then compared as a fraction

so if x=15 when y=24 when x=3

we can set it up as follows

15/24=3/y

15y=72

so y=72/15

Answer 2

In a direct variation you have the situation of y=kx, where k is the constant of variation.

We can solve for k because we know that y is 24 when x is 15. So:

y=kx

24=15k

k=24/15--->k=8/5

Now that we know k we can solve for y when x=3:

y=kx

y=3k

y=3(8/5)

y=24/5

Hope this helps!