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09 Jul 2018, 03:21
1
6
00:00

Difficulty:

75% (hard)

Question Stats:

46% (01:56) correct 54% (02:17) wrong based on 97 sessions

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The original cost of a mobile was $799. Mr. Thomas increased the price by p% and gave a discount of d% on the increased price. Was the new cost less than the original cost? (1) p = d (2) 100p - 100d < pd VP Status: Learning stage Joined: 01 Oct 2017 Posts: 1009 WE: Supply Chain Management (Energy and Utilities) The original cost of a mobile was$799. Mr. Thomas increased the price  [#permalink]

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Updated on: 11 Jul 2018, 01:57
1
1
101mba101 wrote:
The original cost of a mobile was $799. Mr. Thomas increased the price by p% and gave a discount of d% on the increased price. Was the new cost less than the original cost? (1) p = d (2) 100p - 100d < pd New cost=799(1+p-d-pd/100) Original cost=799 new cost-original cost=799(1+p-d-pd/100)-799=799(p-d-pd/100)------(a) St1:- when p=d, then new cost-original cost=-$$799p^2/100$$ Or, (new cost-original cost)<0 Or, New cost is less than original cost. Sufficient. St2:- 100p - 100d < pd Now from (a), we have, New cost-Original cost=799(100(p-d)-pd)/100 So, 799(100(p-d)-pd)) <0 (since 100(p-d)<pd) Therefore,(New cost-Original cost)<0 Or,New cost is less than Original cost. Sufficient. Ans.(D) _________________ Regards, PKN Rise above the storm, you will find the sunshine Originally posted by PKN on 09 Jul 2018, 04:56. Last edited by PKN on 11 Jul 2018, 01:57, edited 1 time in total. Intern Joined: 18 Nov 2017 Posts: 43 Re: The original cost of a mobile was$799. Mr. Thomas increased the price  [#permalink]

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10 Jul 2018, 09:57
PKN wrote:
101mba101 wrote:
The original cost of a mobile was $799. Mr. Thomas increased the price by p% and gave a discount of d% on the increased price. Was the new cost less than the original cost? (1) p = d (2) 100p - 100d < pd New cost=799(1+p-d-pd/100) Original cost=799 Original cost-new cost=799(1+p-d-pd/100)-799=799(p-d-pd/100)------(a) St1:- when p=d, then Original cost-new cost=-$$799p^2/100$$ Or, (Original cost-new cost)<0 Or, Original cost is less than new cost. Sufficient. St2:- 100p - 100d < pd Now from (a), we have, Original cost-new cost=799(100(p-d)-pd)/100 So, 799(100(p-d)-pd)) <0 (since 100(p-d)<pd) Therefore,(Original cost-new cost)<0 Or,Original cost is less than new cost. Sufficient. Ans.(D) Hi PKN, How did you get this? New cost=799(1+p-d-pd/100) VP Status: Learning stage Joined: 01 Oct 2017 Posts: 1009 WE: Supply Chain Management (Energy and Utilities) Re: The original cost of a mobile was$799. Mr. Thomas increased the price  [#permalink]

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10 Jul 2018, 10:33
799 was increased by p%, so price after increment=799(1+p%)
Then Mr. Thomas gave d% discount on this increased price,so new cost price=799(1+p%)(1-d%)

After multiplication,we have
New CP= 799(1-d+p-pd/100) (here all terms viz, p,d and pd are in %)

N.B. p%*d%= (pd)%

Hope it helps.

Posted from my mobile device
_________________
Regards,

PKN

Rise above the storm, you will find the sunshine
Intern
Joined: 18 Nov 2017
Posts: 43

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11 Jul 2018, 00:25
101mba101 wrote:
The original cost of a mobile was $799. Mr. Thomas increased the price by p% and gave a discount of d% on the increased price. Was the new cost less than the original cost? (1) p = d (2) 100p - 100d < pd Ans B in case of p=d=100.....final price will be zero..... so (1) is not sufficient (2) is sufficient Tricky question ....be careful VP Status: Learning stage Joined: 01 Oct 2017 Posts: 1009 WE: Supply Chain Management (Energy and Utilities) Re: The original cost of a mobile was$799. Mr. Thomas increased the price  [#permalink]

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11 Jul 2018, 02:01
101mba101 wrote:
The original cost of a mobile was $799. Mr. Thomas increased the price by p% and gave a discount of d% on the increased price. Was the new cost less than the original cost? (1) p = d (2) 100p - 100d < pd Ans B in case of p=d=100.....final price will be zero..... so (1) is not sufficient (2) is sufficient Tricky question ....be careful Hi, Well it is tricky. As cited by you, when p=d=100 ,the final price is zero. Our question stem is "Was the new cost less than the original original cost?" New cost (0) < original cost(799) ? What is our answer to the above statement: definitely yes.At all instances of p=d, answer to question stem is yes. So st1 is sufficient. Ans (D) Hope it's clear. _________________ Regards, PKN Rise above the storm, you will find the sunshine Intern Joined: 02 Nov 2017 Posts: 30 Location: India Concentration: General Management, Finance GMAT 1: 660 Q49 V29 GPA: 3.31 WE: General Management (Energy and Utilities) The original cost of a mobile was$799. Mr. Thomas increased the price  [#permalink]

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11 Jul 2018, 02:08
PKN wrote:
101mba101 wrote:
The original cost of a mobile was $799. Mr. Thomas increased the price by p% and gave a discount of d% on the increased price. Was the new cost less than the original cost? (1) p = d (2) 100p - 100d < pd Ans B in case of p=d=100.....final price will be zero..... so (1) is not sufficient (2) is sufficient Tricky question ....be careful Hi, Well it is tricky. As cited by you, when p=d=100 ,the final price is zero. Our question stem is "Was the new cost less than the original original cost?" New cost (0) < original cost(799) ? What is our answer to the above statement: definitely yes.At all instances of p=d, answer to question stem is yes. So st1 is sufficient. Ans (D) ....wait wait....yes the question is yes/no. yes you are right. p=d is sufficient. p=d reduces the final result always Director Joined: 14 Dec 2017 Posts: 519 Location: India Re: The original cost of a mobile was$799. Mr. Thomas increased the price  [#permalink]

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11 Jul 2018, 10:59
101mba101 wrote:
The original cost of a mobile was $799. Mr. Thomas increased the price by p% and gave a discount of d% on the increased price. Was the new cost less than the original cost? (1) p = d (2) 100p - 100d < pd Given: Original Cost =$799

New Cost = 799 * (1 + p/100)*(1 - d/100)

Question: is 799 * (1 + p/100)*(1 - d/100) < 799?

Simplified as (100 + p)(100 - d) < 10^4

or 100p - 100d < pd ?

Statement 1: p = d, we get 100p - 100p < p^2

p^2 > 0, which has to be true.

Hence statement 1 is Sufficient.

We can also check for p = d by assuming a value as p = d = 10 & calculating the new price.

we get, New price < Original price

Statement 2: 100p - 100d < pd

As per the simplified version of question stem.

Statement 2 is Sufficient.

Thanks,
GyM
_________________
Manager
Joined: 07 Feb 2017
Posts: 182

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12 Sep 2018, 20:57
1
Experts, is p=d=0? Not an option? Then, price is unchanged.

Posted from my mobile device
Intern
Joined: 03 Apr 2017
Posts: 45

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12 Sep 2018, 23:37
rishit9999 wrote:
Experts, is p=d=0? Not an option? Then, price is unchanged.

Posted from my mobile device

When we say INCREASE or DECREASE in price of any useful thing/material/item, it implies that there is a DEFINITE CHANGE IN PRICE of the item.

p=d=0 implies that there is NO CHANGE OF PRICE, which is a contradicting assumption to the question stem.

Hope it's clear.
_________________
Regards,

PKN

Rise above the storm, you will find the sunshine
Intern
Joined: 01 Mar 2009
Posts: 12
Location: India
GMAT 1: 700 Q48 V38
WE: Information Technology (Computer Software)
Re: The original cost of a mobile was $799. Mr. Thomas increased the price [#permalink] ### Show Tags 13 Sep 2018, 00:02 Thanks pkn. Wanted to be sure about the tricky language of GMAT. Posted from my mobile device Re: The original cost of a mobile was$799. Mr. Thomas increased the price   [#permalink] 13 Sep 2018, 00:02
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