Jack and Mark both received hourly wage increases of 6 perce : GMAT Data Sufficiency (DS)
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# Jack and Mark both received hourly wage increases of 6 perce

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Jack and Mark both received hourly wage increases of 6 perce [#permalink]

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27 Jan 2012, 04:10
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Jack and Mark both received hourly wage increases of 6 percent. After the increases, Jack' hourly wage was how many dollars per hour more than Mark's?

(1) Before the wage increases, Jack's hourly wage is $5 per hour more than Mark's (2) Before the wage increases, the ratio of the Jack's hourly wage to Mark's hourly wage is 4 to 3 [Reveal] Spoiler: Source : Sandeep Gupta – Director, Ivy-GMAT This Q is taken from the source above but the answer is not clear. Q Jack and Mark both received hourly wage increases of 6 percent. After the increases, Jack' hourly wage was how many dollars per hour more than Mark's? (1) Before the wage increases, Jack's hourly wage is$5 per hour more than Mark's
(2) Before the wage increases, the ratio of the Jack's hourly wage to Mark's hourly wage is 4 to 3.

PArt (1) Since the question asks only the difference between 2 qty which has undergone similar percent increase, the difference between the two will also undergo same percent increase. so the answer is 5 * 1.06 . SUFFICIENT

Part (2) the ratio b/w 2 qty will remain the same if the 2 qty will have similar percent change. However knowing the ratio will not help us in calculating the difference. so is INSUFFICIENT

Pl Confirm assumptions used in both parts.
[Reveal] Spoiler: OA

Last edited by Bunuel on 05 Mar 2013, 06:23, edited 2 times in total.
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27 Jan 2012, 04:24
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docabuzar wrote:
Source : Sandeep Gupta – Director, Ivy-GMAT

This Q is taken from the source above but the answer is not clear.

Q Jack and Mark both received hourly wage increases of 6 percent. After the increases, Jack' hourly wage was
how many dollars per hour more than Mark's?
(1) Before the wage increases, Jack's hourly wage is $5 per hour more than Mark's (2) Before the wage increases, the ratio of the Jack's hourly wage to Mark's hourly wage is 4 to 3. PArt (1) Since the question asks only the difference between 2 qty which has undergone similar percent increase, the difference between the two will also undergo same percent increase. so the answer is 5 * 1.06 . SUFFICIENT Part (2) the ratio b/w 2 qty will remain the same if the 2 qty will have similar percent change. However knowing the ratio will not help us in calculating the difference. so is INSUFFICIENT Pl Confirm assumptions used in both parts. Yes, your logic is correct. Jack and Mark both received hourly wage increases of 6 percent. After the increases, Jack' hourly wage was how many dollars per hour more than Mark's? (1) Before the wage increases, Jack's hourly wage is$5 per hour more than Mark's --> no need for algebra here: as wages increase by 6% then the difference between them also increases by the same 6% --> new difference 5*1.06. Sufficient.

(2) Before the wage increases, the ratio of the Jack's hourly wage to Mark's hourly wage is 4 to 3 --> just ratio is not enough to get the value of new difference, as for different hourly wages we'll get different result: bigger the wages the bigger the difference will be. Not sufficient.

P.S. Please post PS questions in the PS subforum: gmat-problem-solving-ps-140/ and DS questions in the DS subforum: gmat-data-sufficiency-ds-141/ No posting of PS/DS questions is allowed in the main Math forum. Thank you.
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Re: Jack and Mark both received hourly wage increases of 6 perce [#permalink]

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11 Jan 2015, 15:40
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Hi All,

Ratios show up on a number of questions on Test Day, so it's important to know your ratio rules (and the various 'formats' that ratios can come in). If you don't immediately see the ratio rules that appear in this question, you can still get to the correct answer by TESTing VALUES.

We're told that Jack and Mark each receive a raise of 6% to their hourly wages. We're asked how much larger Jack's hourly wage is AFTER the increases.

Fact 1: Before the increases, Jack's wage was $5/hour more than Mark's wage IF.... Jack =$10/hour
Mark = $5/hour After the raises..... Jack = 10(1.06) = 10.60 Mark = 5(1.06) = 5.30 So.....Jack's wage is$5.30 more than Mark's

IF....
Jack = $11/hour Mark =$6/hour
After the raises....
Jack = 11(1.06) = 11.66
Mark = 6(1.06) = 6.36
So....Jack's wage is $5.30 more than Mark's The result STAYS$5.30 even when the numbers change, so $5.30 is THE difference. Fact 1 is SUFFICIENT Fact 2: Before the raises, the ratio of Jack's wage to Mark's wage was 4:3 IF..... Jack =$4/hour
Mark = $3/hour After the raises.... Jack = 4(1.06) = 4.24 Mark = 3(1.06) = 3.18 So....Jack's wage is$1.06 more than Mark's

IF....
Jack = $8/hour Mark =$6/hour
After the raises....
Jack = 8(1.06) = 8.48
Mark = 6(1.06) = 6.36
So....Jack's wage is $2.12 more than Mark's These two results are DIFFERENT. Fact 2 is INSUFFICIENT Final Answer: [Reveal] Spoiler: A GMAT assassins aren't born, they're made, Rich _________________ # Rich Cohen Co-Founder & GMAT Assassin # Special Offer: Save$75 + GMAT Club Tests

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Re: Jack and Mark both received hourly wage increases of 6 perce [#permalink]

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10 Jun 2013, 02:52
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Re: Jack and Mark both received hourly wage increases of 6 perce [#permalink]

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30 Mar 2015, 06:46
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1) x and x+5 are the wages. After increase, their wages : 1.06x and 1.06x+1.06*5. Thus diff = 1.06*5. SUFF.
2) x and 4x/3 are the wages. After increase, their wages : 1.06x and 1.06*4*x/3. Thus diff contains x. Not SUFF.

Ans A.
(I use symbol x for clarity. No need to calculate the value of x, since we know that by taking the diff, the x term cancels in 1 but remains in 2)
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27 Jan 2012, 04:19
Hi,

I dont know if this solution is right or not but made sense to me.... Let me knw if my logic is wrong or not

We need to find Diff =1.06( Jacks' Hourly Wage (J)) -1.06 ( Mark's Hourly Wage (M) )

A ] Sufficient

Diff = 1.06J - 1.06M - Eqn 1
J= M+5 Substitue in Eqn 1 & you get 5

B] Sufficient

J/M = 4/3 => J = 4M/3

You can get a solution for the same as used in A

Therefore D

Hope this helps....
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Re: Jack and Mark both received hourly wage increases of 6 perce [#permalink]

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26 Jun 2014, 10:18
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Re: Jack and Mark both received hourly wage increases of 6 perce [#permalink]

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11 Jan 2015, 00:06
Jack and Mark both received hourly wage increases of 6 percent. After the increases, Jack' hourly wage was how many dollars per hour more than Mark's?

(1) Before the wage increases, Jack's hourly wage is $5 per hour more than Mark's (2) Before the wage increases, the ratio of the Jack's hourly wage to Mark's hourly wage is 4 to 3 (1) M before x J before x+5 M after x*1.06 J after (x+5)*1.06 J after - M after = (x+5)*1.06-x*1.06 ---> 1.06(x+5-x) ---> 1.06*5 . Sufficient . (2) M before 3x J before 4x M after 3x*1.06 J after 4x*1.06 J after - M after = 4x*1.06-3x*1.06 ---> 1.06(4x-3x) ---> 1.06*x ---> value of x?. Not Sufficient . Answer A. Veritas Prep GMAT Instructor Joined: 16 Oct 2010 Posts: 7125 Location: Pune, India Followers: 2137 Kudos [?]: 13684 [0], given: 222 Re: Jack and Mark both received hourly wage increases of 6 perce [#permalink] ### Show Tags 31 Mar 2015, 00:09 Expert's post 1 This post was BOOKMARKED docabuzar wrote: Jack and Mark both received hourly wage increases of 6 percent. After the increases, Jack' hourly wage was how many dollars per hour more than Mark's? (1) Before the wage increases, Jack's hourly wage is$5 per hour more than Mark's
(2) Before the wage increases, the ratio of the Jack's hourly wage to Mark's hourly wage is 4 to 3

[Reveal] Spoiler:
Source : Sandeep Gupta – Director, Ivy-GMAT

This Q is taken from the source above but the answer is not clear.

Q Jack and Mark both received hourly wage increases of 6 percent. After the increases, Jack' hourly wage was
how many dollars per hour more than Mark's?
(1) Before the wage increases, Jack's hourly wage is $5 per hour more than Mark's (2) Before the wage increases, the ratio of the Jack's hourly wage to Mark's hourly wage is 4 to 3. PArt (1) Since the question asks only the difference between 2 qty which has undergone similar percent increase, the difference between the two will also undergo same percent increase. so the answer is 5 * 1.06 . SUFFICIENT Part (2) the ratio b/w 2 qty will remain the same if the 2 qty will have similar percent change. However knowing the ratio will not help us in calculating the difference. so is INSUFFICIENT Pl Confirm assumptions used in both parts. An interesting thing to note here is that statement 1 uses the same concept as compound interest. In compound interest, you earn the rate of interest not only on the principal but also on the interest earned till then. We know that Jack's hourly wage is$5 more than Mark. When their wages increase by 6%, Jack earns an extra increase of 6% of $5. So now Jack's wage will be$5+$0.3 =$5.3 more than Mark's wage.

Statement 2 gives us a ratio of wages and not the actual wages. Hence, without any actual number, there is no way we can find the difference in their wages.
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(2) Before the wage increases, the ratio of the Jack's hourly wage to Mark's hourly wage is 4 to 3

The difference after increases will be: 1.06J-1.06M=1,06(J-M)
(1) Just insert this information (J-M=5 before increases) in the expression above -> 1.06*5 Sufficient
(2) We need a concrete value, the ratio alone is not sufficient
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Re: Jack and Mark both received hourly wage increases of 6 perce [#permalink]

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07 Jan 2017, 06:37
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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Re: Jack and Mark both received hourly wage increases of 6 perce   [#permalink] 07 Jan 2017, 06:37
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