Question

In a cookie-eating contest, Luke ate 8 cookies in 1 minute and 30 seconds. At this rate, how many cookies will he eat in 3 minutes and 45 seconds?

Answer 1

If it took him 1 minute and 30 seconds to eat 8 cookies, in 3 minutes and 45 seconds he could eat 20 cookies.(3 minutes and 45 seconds is 225 seconds. 1 minutes and 30 seconds is 90 seconds. 225/90=2.5, 2.5•8=20)

Answer 2

20 cookies

Explanation:

Change from minutes and seconds to seconds

1 minute 30 seconds = 90 seconds

3 minutes 45 seconds = 3 *60 +45 = 180+45 = 225 seconds

Now we can use ratios to solve

8 cookies x cookies

------------- = -----------------

90 seconds 225 seconds

Using cross products

8 * 225 = 90x

Divide each side by 90

1800/90 = 90x/90

20 =x