Question

Kelly ran 2 miles burned 240 cal. The next day she ran 3 miles and burned 360 cal. The next day 4 miles 480 miles.If this pattern continues,how many cal. will she burn if she run 8 miles?

Answer 1

Kelly will burn 960 calories if she runs 8 miles

Answer 2

`960\ cal`

Explanation:

we know that

A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form
`y/x=k` or
`y=kx`

Let

x-----> the number of miles

y------> the number of calories

For
`x=2\ miles, y=240\ cal`

`k=y/x=240/2=120`

For
`x=3\ miles, y=360\ cal`

`k=y/x=360/3=120`

For
`x=4\ miles, y=480\ cal`

`k=y/x=480/4=120`

therefore

Is a linear direct variation

The equation is equal to

`y=120x`

so

For
`x=8\ miles`

Find the value of y

substitute in the equation

`y=120(8)=960\ cal`