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# A can complete a certain job in 12 days. B is 60%

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Current Student
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A can complete a certain job in 12 days. B is 60% [#permalink]

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02 Jun 2014, 07:09
1
5
00:00

Difficulty:

35% (medium)

Question Stats:

72% (01:07) correct 28% (01:05) wrong based on 298 sessions

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A can complete a certain job in 12 days. B is 60% more efficient than A. In how many days can B complete the same job?

(A) 6
(B) 6.25
(C) 7
(D) 7.5
(E) 4.8

Kudos if you like the question..

Little awkward explanation.60% more efficient means B can do 160% of work in same no. of days as A takes to do 100% of work.
160% work in 12 days
100% work in x days
x = $$\frac{(12*100)}{160}$$
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Joined: 02 Sep 2009
Posts: 46214
Re: A can complete a certain job in 12 days. B is 60% [#permalink]

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02 Jun 2014, 07:29
b2bt wrote:
A can complete a certain job in 12 days. B is 60% more efficient than A. In how many days can B complete the same job?

(A) 6
(B) 6.25
(C) 7
(D) 7.5
(E) 4.8

Kudos if you like the question..

Little awkward explanation.60% more efficient means B can do 160% of work in same no. of days as A takes to do 100% of work.
160% work in 12 days
100% work in x days
x = $$\frac{(12*100)}{160}$$

B is 60% more efficient than A, means that the rate of B is 1.6 times as greater as that of A.

So, if A can complete the job in 12 days, then B complete the same job in 12/1.6 = 12/(8/5) = 15/2 = 7.5 days.

P.S. Not exactly a GMAT wording.
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Re: A can complete a certain job in 12 days. B is 60% [#permalink]

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12 Jul 2015, 03:52
b2bt wrote:
A can complete a certain job in 12 days. B is 60% more efficient than A. In how many days can B complete the same job?

(A) 6
(B) 6.25
(C) 7
(D) 7.5
(E) 4.8

Kudos if you like the question..

Little awkward explanation.60% more efficient means B can do 160% of work in same no. of days as A takes to do 100% of work.
160% work in 12 days
100% work in x days
x = $$\frac{(12*100)}{160}$$

Set up a Rate Time Work Table and plug in the values:

Rate / Time / Work for A:
12 / 12 / 144

Rate / Time / Work for B:
19.2 / 7.5 / 144

Do not fall into the trap by just working with the time, i.e. taking 60% off from 12 days and subtracting it from 12. Trap Answer E.
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Re: A can complete a certain job in 12 days. B is 60% [#permalink]

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12 Jul 2015, 06:05
2
5
b2bt wrote:
A can complete a certain job in 12 days. B is 60% more efficient than A. In how many days can B complete the same job?

(A) 6
(B) 6.25
(C) 7
(D) 7.5
(E) 4.8

Alternate Method

Let, Total Work Unit = 120 Units

A can finish in 12 days = 120 unit work
i.e. A can finish in 1 days = 10 unit work
i.e. B can finish in 1 days = 10+(60/100)*10 = 16 unit work

Days in which B will complete the work alone = 120/16 = 30/4 = 7.5 days

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Re: A can complete a certain job in 12 days. B is 60% [#permalink]

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12 Jul 2015, 10:18
Let the number of units of work done by A in one day = 10, so B does 16 units of work per day.

Total units of work done by A = 12*10 = 120 units.

No. of days taken by B to do 120 units of work = 120/16 = 7.5. Ans (D).
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Re: A can complete a certain job in 12 days. B is 60% [#permalink]

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18 Apr 2017, 10:37
You could even do process elimination

7 x 1 3/5
56/5 or 11 1/5 Not the answer. Let's use a big number

D - 7 1/2 x 1 3/5
15/2 x 8/5
12

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Re: A can complete a certain job in 12 days. B is 60% [#permalink]

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08 Mar 2018, 17:44
1
b2bt wrote:
A can complete a certain job in 12 days. B is 60% more efficient than A. In how many days can B complete the same job?

(A) 6
(B) 6.25
(C) 7
(D) 7.5
(E) 4.8

The rate of A is 1/12.

Since B is 60% more efficient the rate of B is 1.6 x 1/12 = 1.6/12 = 16/120 = 2/15.

Since time is inverse of rate, B can complete the job in 15/2 = 7.5 days.

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Re: A can complete a certain job in 12 days. B is 60%   [#permalink] 08 Mar 2018, 17:44
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