pour 7/8 of a full cup out, then add back 40% of the cup- what percent of the cup remains empty?

How to solve a fraction and percent math word problem.
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[@simev500]

It's either 47-1/2% or, 80-1/2% of the cup remains empty. Depending on whether the cup was backfilled with 40% of the original volume or 40% of what remained ( the 1/8) in the cup AFTER the 7/8 was taken out.

[@bluejedi723]

now why the hell would I pour liquid out of a cup (I'm assuming on purpose here) just to add some back? I don't understand.

[@oldmcfarlane]

So that you could have enough people watch you explain the math behind it that it paid for your house.

[@philrobson4287]

A cup is 8 oz. Take out 7/8 of it and you have 1 oz. Add 40% of 8 oz (3.2oz). Now there’s 4.2 oz in the cup leaving 3.8oz missing which is 47.5% empty.

[@tomtke7351]

Hope we are talking portions of the cup in both instances.. as in we take 7/8's of a cup out and then put 4/10'ths of a cup back in final equation: Total = 1 - (7/8) + (4/10) = 1 -(35/40) +(16/40) = (40-35+16)/40 = 21/40 = 52.5% full = 47.5% empty

[@MrMousley]

If we pour out 7/8 of the cup that would leave it 1/8 full (1/4 is 25% so 1/8 is 12.5%) We then add 40% 40% + 12.5% = 52.5% FULL and we want EMPTY 100% - 52.5% = 47.5% EMPTY

[@juddbiggs]

Yup..was my way too?🙂🙂

[@russelllomando8460]

Got it, good one. Thanks.

[@devonwilson5776]

Greetings. The answer is 47.5%. After we have poured out 7/8 of the cup's contents we would have 1/8 remaining. Thereafter, if we add back 40%, the amount remaining should 1/8+2/5=(5+16)/40=21/40. This value represents the portion of the cup that is filled. Therefore, to determine the% of the cup that is empty, we need to subtract this value from 1 and multiply the difference by 100%. That is (1-21/40)×100%=(19/40×100%= 47.5%. Lovely.

[@marinecorpswarrior915]

Easier and faster convert the 1/8 that is reminding in the cup to a decimal which would be 12.5 then convert the 40% that's been added back to a decimal (.40) and add it to the 12.5 which would be 52.5 then subtract: 100-52.5=47.5

[@Melanheadmilo]

I HATED my math teachers in high school because they ask questions just like this that can be interpreted differently.

[@Vipre-]

I'm interested to hear how you would interpret it. The only reasonable possibilities would be 47.5%, 52.5%, and 60%

[@Melanheadmilo]

@@Vipre- its me. I read it wrong. just like in high school. When I actually read it correctly, I got it right. Love your channel

[@edsherrod5216]

I had a teacher in the 7th grade that drilled us daily on converting fraction to decimal and back daily, so this one I could do in my head...

[@dbdriggers3690]

Thank you wish I Had You for my math teacher In school

[@GoofballFlyer]

🤔 (1 - 7/8 + 0.4 = 0.475)*100 = 47.5% and a great point on understanding the problem!

[@paulhaye]

100 - 52.5 = 47.5.

[@kiedd1]

I was able to do it in my head, in a slightly easier way. Instead of turning 7/8 to decimal, I thought of the 1/8 that remains. That's half of a quarter, so half of .25, which gave me the 12.5%. The rest just fell into place.

[@paulhaye]

Decimal, why? Just get the percentage of 7/8. In Jamaica we cross multiply then divide. Eg ?/100 7/8 = 100x7/8 = 87.5. The rest is quite easy.

[@sekharb6651]

47.5%

[@billhawkesworth990]

47.5

[@ciderman1950]

52.5%

[@santanamargiela]

3/8%

[@charlesmitchell5841]

47.5% remains empty

[@williamlynch1929]

Just under half is empty at .475

[@armincagoodwin367]

I share your math with grandson

[@charlesbusch8739]

Why do you keep repeating all your information on each video?

[@sarahskaggs8828]

Ok. I said 45% as my original answer. Not far off. However, would 7/8 be the same as 3/4 in terms size? My thinking, is 7/8 of a full cup is the same as 3/4 of a full cup. I just used that.

[@williamkirkconnell7306]

47.5%