Question

could someone please help me?

Sharon has 8 cups of granola. She eats 2/3 cup each day. How long will her granola last?

could someone please help me to understand and what to do? :)

Answer 1

Let's make a different problem. Say Sharon eats 1 cup of granola each day. Can you tell me how long it will last?

Answer 2

8 days and thx for helping me :D

Answer 3

You're welcome. How about if she eats 2 cups each day?

Answer 4

4 days

Answer 5

Right. So how did you find those answers?

Answer 6

umm... sorry but I don't know?? lol its just easy

Answer 7

But what was the process?

Answer 8

You divided the amount she had by the amount she ate each day, right?

Answer 9

YES! that's a great way to put it lol

Answer 10

Okay, well, what if she ate half a cup a day? How long would it last?

Answer 11

um.. 16 days?

Answer 12

Yep! Now, here's where it might get a bit tricky. What if she eats 2/3 of a cup each day? :-)

Answer 13

Do you know how to divide by a fraction?

Answer 14

24???????

Answer 15

That would be the right answer, if only I had asked how long it would last if she ate 1/3 of a cup each day...

Answer 16

But she ate twice that — 1/3 cup in the morning, and 1/3 cup at night :-)

Answer 17

2/3 divied by 8= 0.0833333

Answer 18

You have your problem backwards. She has 8 cups, and eats 2/3 of a cup each day. We can divide 8 cups into how many 2/3 cup servings?

Answer 19

You were on the right track when you said 24, if you'd followed through with what I said...

You said the granola would last for 24 days. I pointed out that that was the correct answer if she eats 1/3 of a cup each day, but in fact, she eats twice as much.

If eating 1/3 of a cup each day will exhaust her supply in 24 days, if she eats twice as much each day, how long will the supply last?

Answer 20

If you spend your money twice as fast, doesn't it only last half as long? What is half of 24 days?

Answer 21

12! :D

Answer 22

Right. Now, I think you need to learn how to divide by fractions. Good news: it's easy!

Dividing by a fraction is the same as multiplying by the fraction, after you turn the fraction upside down.

So, \[\frac{8}{\frac{2}{3}} = 8*\frac{3}{2} = \frac{3*8}{2} = \frac{24}{2} = 12\]

Answer 23

Or to use another example that we touched:
\[\frac{8}{\frac{1}{2}} = 8*\frac{2}{1} = \frac{8*2}{1} =\frac{16}{1} = 16\]

Answer 24

yup its 12

Answer 25

awesome