Question: Figs and Prunes

Comment on Figs and Prunes

Brent,

I got the same result, but I did in a different way, could you check if I did correctly, please?

Yesterday = F + P, we know F = P, so Yesterday = 2F
Now = (F-24) + P, we know P = 3F, so Now = (F-24) + 3F

With these two equations we can say Yesterday = Now
So: 2F = (F-24) + 3F --> 2F = 4F - 24 --> 4F - 2F = 24 --> 2F = 24 --> Fnow = 12, then Pnow = 3x12 = 36
Now = 12 + 36 = 48

I thing it is not the correctly approach, but I got the same answer.

Help me please.

Thanks,
Pedro
gmat-admin's picture

Your correct solution was a coincidence.
In your solution, you say there were F figs and P prunes YESTERDAY.
So, when you solve your equation to get F = 12, this means there were 12 figs yesterday, which is impossible since Cherif ate 24 figs this morning.

Also, if there are F-24 figs today (after Cherif eats 24 figs), then the number of prunes TODAY = 3(F-24), not 3F
Also, YESTERDAY the number of prunes = P = F

Since the number of prunes doesn't change from yesterday to today, we can write: (number of prunes yesterday) = (number of prunes today)
Substitute to get: F = 3(F-24)
Solve to get: F = 36, which means there were 36 figs and 36 prunes yesterday.

If there were 72 pieces of fruit yesterday, the number of pieces of fruit today = 72 - 24 = 48

I hope that helps.

3 times as many prunes as figs...confusing
gmat-admin's picture

Perhaps, but that's the kind of wording you'll see on test day.

Hey Brent!
You suggested at the beginning of the video that we can test the answer choices to solve this problem! Can you explain please!
Many thanks
gmat-admin's picture

Sure thing.

Let's test answer choice C (60).
If 60 = total number of figs and prunes NOW, and there are 3 times as many prunes as figs, then there are NOW 15 figs and 45 prunes.

If Cherif previously ate 24 figs, then the ORIGINAL number of figs = 15 + 24 = 39
So, ORIGINALLY, there were 39 figs and 45 prunes.

HOWEVER, we're told that we ORIGINALLY had an EQUAL number of figs and prunes.
ELIMINATE C
-----------------------------
Now try answer choice B (48)

If 48 = total number of figs and prunes NOW, and there are 3 times as many prunes as figs, then there are NOW 12 figs and 36 prunes.

If Cherif previously ate 24 figs, then the ORIGINAL number of figs = 12 + 24 = 36
So, ORIGINALLY, there were 36 figs and 36 prunes.
PERFECT!

Cheers,
Brent

initially figs were equals prunes F=P the rate is 1:1
after Cherif ate 24 the rate is 3:1
eaten Figs to none eaten is the same 24:8
so total Figs were 32, total figs+ prunes 72 and remaining become 48
gmat-admin's picture

Perfect!

Hi Brent, in Pedro's post above where it says, "we can say Yesterday = Now", can you please elaborate why?

When we solve the 2 equations set equal to each other, we get F=12 and Pedro specifies that it's Fnow = 12, but wasn't F defined as the number of figs in the bag yesterday?

Thank you!
gmat-admin's picture

You're absolutely right.
I think I read his solution too quickly.
I have edited my response accordingly.
Thanks for the heads up!

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