GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
If (3 + a)(a/10 - 0.4) = -1, then a could be
[#permalink]
01 Mar 2021, 10:35
01 Mar 2021, 10:35
Expert Reply
00:00
Question Stats:
80% (02:07) correct
20% (01:57) wrong based on 20 sessions
Hide Show timer Statistics
If \((3 + a)(\frac{a}{10} - 0.4) = -1\), then a could be
A. -4
B. -2
C. 1
D. 2
E. 4
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
A. -4
B. -2
C. 1
D. 2
E. 4
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: If (3 + a)(a/10 - 0.4) = -1, then a could be
[#permalink]
01 Mar 2021, 12:01
01 Mar 2021, 12:01
Carcass wrote:
If \((3 + a)(\frac{a}{10} - 0.4) = -1\), then a could be
A. -4
B. -2
C. 1
D. 2
E. 4
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
A. -4
B. -2
C. 1
D. 2
E. 4
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
One approach is to eliminate the fractions/decimals first.
Given: (3 + a)(a/10 - 0.4) = -1
Multiply both sides by 10 to get: (3 + a)(a/10 - 0.4)(10) = (-1)(10)
Simplify: (3 + a)(a - 4) = -10
Expand and simplify: a² - a - 12 = -10
Add 10 to both sides: a² - a - 2 = 0
Factor: (a + 1)(a - 2) = 0
So, EITHER a = -1 OR a = 2
Answer: D
Alternatively, once you get to the point where you have the equation (3 + a)(a - 4) = -10, you could easily plug in the answer choices until you found the one that satisfies the equation (3 + a)(a - 4) = -10
Cheers,
Brent
gmatclubot
Re: If (3 + a)(a/10 - 0.4) = -1, then a could be [#permalink]
01 Mar 2021, 12:01
Moderators:
