Question

While riding her bike, Susan burns 450 calories every 1/2 hour. Based on this rate, how many calories will Susan burn if she rides the bike for 1 3/4?

Answer 1

1575 calories. 225 calories per 15 mins so 225 times 7 is 1575

Answer 2

Susan will burn 1,575 calories.

Explanation:

Let's turn these numbers into ratios.

`(450)/((1)/(2) ) = (x)/((7)/(4) )` (I turned the mixed number into an improper fraction for simplicity's sake)

Looks a bit messy. Let's flip some numbers around and make it look neater.

`(450*2)/(1)  = (4x)/(7)`

`900 = (4x)/(7)`

That's better! Let's now multiply each side by 7 and solve for x:

`900*7 = (4x)/(7) * 7`

`6300 = 4x`

`(6300)/(4) = (4x)/(4)`