BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Cost is expressed

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 421
Joined: Sun Apr 17, 2011 4:27 am
Location: India
Thanked: 6 times
Followed by:2 members
GMAT Score:620

Cost is expressed

by vinni.k » Tue Nov 01, 2011 1:03 pm
*source:- "MGMAT"

Please help in solving the following question.

Cost is expressed by the formula tb^4. If b is doubled, by what factor has the cost increased ?

(A) 2
(B) 6
(C) 8
(D) 16
(E) 1/2

Answer is D

Regards
Vinni
Top
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 489
Joined: Tue Jul 05, 2011 11:10 am
Thanked: 28 times
Followed by:5 members

by gmatblood » Tue Nov 01, 2011 1:07 pm
IMO: 16

Cost is expressed by the formula tb^4. If b is doubled, by what factor has the cost increased ?

(A) 2
(B) 6
(C) 8
(D) 16
(E) 1/2

sub:

original: t=1, b=2 : tb^4 = 16
modified: t=1, b=4(doubled) : tb^4 = 256

Modified/original = 16
Top
Legendary Member
Posts: 966
Joined: Sat Jan 02, 2010 8:06 am
Thanked: 230 times
Followed by:21 members

by shankar.ashwin » Tue Nov 01, 2011 8:34 pm
Cost = t * b^4

New Cost = t * (2b)^4 = t * 16 b ^4

New Cost = 16 Cost
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 421
Joined: Sun Apr 17, 2011 4:27 am
Location: India
Thanked: 6 times
Followed by:2 members
GMAT Score:620

by vinni.k » Wed Nov 02, 2011 9:04 am
I tried with few more smart numbers. Got it.

Thanks shankar.ashwin and gmatblood.

Regards
Vinni
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 416
Joined: Tue Aug 30, 2011 2:18 pm
Location: Delhi, India
Thanked: 13 times
Followed by:9 members

by vaibhavgupta » Wed Nov 02, 2011 1:10 pm
vinni.k wrote:*source:- "MGMAT"

Please help in solving the following question.

Cost is expressed by the formula tb^4. If b is doubled, by what factor has the cost increased ?

(A) 2
(B) 6
(C) 8
(D) 16
(E) 1/2

Answer is D

Regards
Vinni
tb^4 .. t(2b)^4= 2*2*2*2*tb^4= 16tb^4 ..

Hence D it is! :)
If OA is A, IMO B
If OA is B, IMO C
If OA is C, IMO D
If OA is D, IMO E
If OA is E, IMO A

FML!! :/
Top
Post new topic Post Reply
• Page 1 of 1