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Comment on Tips for the Input-Output Approach
Great tips
Hi! If you were to solve this
You're referring to the
You're referring to the question that appear at 6:23 in the above video.
You have: (1 + y/100 + x/100 + xy/100²) - 1
Rewrite first part with denominator 100²
We get: (100²/100² + 100y/100² + 100x/100² + xy/100²) - 1
Combine the first 4 terms: (100² + 100y + 100x + xy)/100² - 1
Factor top part to get: (100 + x)(100 + y)/100² - 1
Hmmm, I have a feeling your first expression, (1 + y/100 + x/100 + xy/100²) - 1, is incorrect.
Can you tell me how you got to (1 + y/100 + x/100 + xy/100²) - 1?
Cheers,
Brent
Hi Brent, could you show the
Let W = the value of the
Let W = the value of the investment on Wednesday.
So, from the given info, we know that (1 + x/100)W = the value on Thursday.
And, from the given info, we know that (1 + y/100)(1 + x/100)W = the value on Friday.
So, the % increase from Wednesday to Friday = (100)(Friday's value - Wednesday's value)/Wednesday's value
In other words: The % increase = (100)[(1 + y/100)(1 + x/100)W - W]/W
Multiply numerator and denominator by 100 to get: (100)(100)[(1 + y/100)(1 + x/100)W - W]/(100)W
Simplify: [(100 + y)(100 + x)W - 10,000W]/100W
Simplify: (100 + y)(100 + x)/100 - 100
Answer: B
Great thanks Brent. In the
Were using the general
Were using the general property that says (a - b)/c = a/c - b/c
So for our expression we get:
[(100 + y)(100 + x)W - 10,000W]/100W = [(100 + y)(100 + x)W]/100W - 10,000W/100W
= [(100 + y)(100 + x)]/100 - 100
Does that help
Ah get it and not sure why
At his regular hourly rate,
cost of a repair job as $336 and he was paid that
amount. However, the job took 4 hours longer than
he had estimated and, consequently, he earned
$2 per hour less than his regular hourly rate. What was
the time Don had estimated for the job, in hours?
(A) 28
(B) 24
(C) 16
(D) 14
(E) 12
sir how to solve this question?
Hi Manjot,
Hi Manjot,
https://gmatclub.com/forum/at-his-regular-hourly-rate-don-had-estimated-...
Cheers,
Brent
https://gmatclub.com/forum
sir please explain.
At the risk of appearing
At the risk of appearing super lazy, I've seen Mitch (GMATGuruNY) post this great solution several times, and I think it's perfect: https://www.beatthegmat.com/og-13-ps-218-is-this-prob-really-doable-with... (Mitch's solution is the 4th post)
He also provides some great advice about the potential to skip (guess) and move on!
If you need any clarification regarding Mitch's solution, please let me know.
Cheers,
Brent
Hi Brent,
Is there an easy way to solve the below question:
https://gmatclub.com/forum/from-2000-to-2003-the-number-of-employees-at-a-certain-company-increa-268694.html
Here's my full solution:
Here's my full solution: https://gmatclub.com/forum/from-2000-to-2003-the-number-of-employees-at-...
Cheers,
Brent
As you mentioned, an
If so, I assume you're just using it as an example to demo the *input-output* technique, even though there is an algebraic solution, correct?
Thanks.
Yes, I'm using the input
Yes, I'm using the input-output for this question so I can demonstrate the strategy.
Regarding the second question
Given the fact of question, "x percent greater than it's value on Wednesday", if we plug 0 into x which does not make sense at all ?
Please help !
Thanks.
I believe you're referring to
I believe you're referring to the question that starts at 6:22 in the video above.
It's perfectly fine to have an "increase" of 0%. This Just means there was no increase.
For example, if Townville had a population of 10,000 in 2018, and a population of 10,000 in 2019, then we can say that the population "increased" 0% from 2018 to 2019. In other words, the population in 2019 is 0% greater than the population in 2018.
Does that help?
Another great video Brent.
https://gmatclub.com/forum/a-piece-of-twine-of-length-t-is-cut-into-two-pieces-the-length-of-the-270620.html
t= 2 + 3s
20 = 2+3s
6 = s
L = 2+18 = 20
Question link: https:/
Question link: https://gmatclub.com/forum/a-piece-of-twine-of-length-t-is-cut-into-two-...
I think you would benefit from carefully detailing each step of your solution (e.g., clearly defining your variables and detailing each step you take).
Doing so will help you identify errors.
In your solution, you let t (the TOTAL length of twine) equal 20.
You later say s (the length of the shorter piece) = 6,
and L (the length of the longer piece) = 20
Notice that the length of the longer piece (20) is equal to the TOTAL length of twine (t)
If the length of the shorter piece = 6, and the length of the longer piece = 20, then t = 6 + 20 = 26.
In other words, the total length (t) of the twine is 26.
If you plug (input) t = 26 into each answer choice you will eventually get...
(E) (3t + 2)/4 = [(3)(26) + 2]/4 = 80/4 = 20, which is the length of the longer piece (i.e., the output).
Sure thanks Brent. Think I