Jack and Mark both received hourly wage increases of 6 perce

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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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:

GMAT assassins aren't born, they're made,
Rich

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)

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.

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
Answer A

Ok so two dudes are getting a wage increase, lucky them. We want to know what the difference between their salaries is after the 6% increase.

What are we solving for? Asking yourself that question may seem silly, but it is a really important habit to form, because you need to know what you're looking for in the statements.

1.06*J - 1.06*M = ?
1.06*(J - M) = ?

Statement 1: Before increase, Jack's salary $5 more than Mark's.

J = M + 5

Almost what we want, just re-arrange:

J - M = 5

Cool, now plug that into the re-phrased question:

1.06*(J - M) = ?
1.06*(5) = 5.3

You've got a value so you can stop (you didn't need to actually work it out)!

Statement 2: Before the increase the ratio of Jack's hourly wage to Mark's hourly wage was 4 to 3.

You might immediately see, as some posters did, that you cannot get a concrete value from a ratio. Mike McGarry had a really good blog post about that I read a while back. Given that the question is asking about a concrete value, and this statement gives you only a ratio, you can just immediate discard this.

Let's just suppose for a moment that you didn't see that, you would do this:

J/M = 4/3
J = (4/3)*M

Ok, try that with our re-phrased question:

1.06*((4/3)*M - M) = ?
1.06*((1/3)*M) = ?

You can't get rid of that M, so you cannot get an actual value to answer the question.

(A)

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