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Sub 505 Level|   Arithmetic|   Number Properties|               
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tarek99
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 Q49  V35
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If a = 1 and (a - b)/c = 1 which of the following is NOT a possible va Updated on: 08 Oct 2018, 03:43
Originally posted by tarek99 on 11 Dec 2007, 03:22.
Last edited by Bunuel on 08 Oct 2018, 03:43, edited 3 times in total.
Renamed the topic and edited the question.
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Question Stats:

82% (01:12) correct 18% (01:29) wrong based on 1911 sessions

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If a = 1 and (a - b)/c = 1 which of the following is NOT a possible value of b?

A. -2
B. -1
C. 0
D. 1
E. 2
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D
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Bunuel
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If a = 1 and (a - b)/c = 1 which of the following is NOT a possible va 01 Mar 2012, 00:10
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imhimanshu
Hi.
Can anyone let me know what is wrong in my approach -

(a-b)/c = 1

a-b = c(by cross multiplying)
Now as a= 1
1-b = c
implies, 1-c=b
Now c can take any value, and b can have any of the values provided in the answer choices. Please let me know where I am going wrong. Why it is not possible to cross multiply in the first instance. this is how I approached in my exam.

Thanks

If a=1 and (a-b)/c = 1 which of the following is NOT a possible value of b?

A. -2
B. -1
C. 0
D. 1
E. 2

First of all remember that division by zero is undefined, hence \(c\neq{0}\) and that's why you CAN cross-multiply.

\(\frac{a-b}{c}=1\)

Since \(a=1\), then

\(\frac{1-b}{c}=1\);

\(1-b=c\)

But since \(c\neq{0}\), then \(1-b\neq{0}\), thus \(b\neq{1}\).

Answer: D.

Hope it's clear.
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If a = 1 and (a - b)/c = 1 which of the following is NOT a possible va 11 Dec 2007, 19:57
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tarek99
If a=1 and (a-b)/c = 1 which of the following is NOT a possible value of b?

A. -2
B. -1
C. 0
D. 1
E. 2

b = (1-c)

If b=1, then C=0, which will not satisfy (a-b)/c = 1. ( divisibility by 0 is not possible.)

therefore b=1 is not possible.
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eschn3am
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If a = 1 and (a - b)/c = 1 which of the following is NOT a possible va 12 Dec 2007, 06:53
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yezz
tarek99
If a=1 and (a-b)/c = 1, which of the following is NOT a possible value of b?

a) -2

b) -1

c) 0

d) 1

e) 2

all r possible


Equation is:

(a-b)/c = 1 where a = 1

so plug in 1 for a and look at it again

(1-b)/c = 1

now C can be anything we want, so if b = -2 we can plug it in and make it work

(1-(-2))/c = 1
3/c = 1
c = 3 and it works

HOWEVER, if we have a 0 in the numerator there isn't a number on earth that makes 0/C = 1

(1-1)/c = 1
0/c = 1
there aren't any matches for C to make this true

B cannot be 1.

Answer is D
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If a = 1 and (a - b)/c = 1 which of the following is NOT a possible va 29 Feb 2012, 22:51
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Hi.
Can anyone let me know what is wrong in my approach -

(a-b)/c = 1

a-b = c(by cross multiplying)
Now as a= 1
1-b = c
implies, 1-c=b
Now c can take any value, and b can have any of the values provided in the answer choices. Please let me know where I am going wrong. Why it is not possible to cross multiply in the first instance. this is how I approached in my exam.

Thanks
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If a = 1 and (a - b)/c = 1 which of the following is NOT a possible va 25 May 2017, 23:00
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If a=1, then (a-b)/c = (1-b)/c which is given to be = 1

Obviously b cannot be equal to 1, because then (1-b) will become 0, which is not possible.

Hence D answer
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If a = 1 and (a - b)/c = 1 which of the following is NOT a possible va 31 May 2017, 19:07
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zisis
If a=1 and (a-b)/c = 1 which of the following is NOT a possible value of b?

A. -2
B. -1
C. 0
D. 1
E. 2

If a = 1, we have:

(1 - b)/c = 1

1 - b = c

We must also remember that since (1 - b)/c = 1, and since dividing by zero creates an undefined result, c cannot be zero.

Let’s test the answer choices:

A) -2

Since c = 1 - (-2) = 3, b could be -2.

B) -1

Since c = 1 - (-1) = 2, b could be -1.

C) 0

Since c = 1 - 0 = 1, b could be 0.

D) 1

Since c = 1 - 1 = 0, b cannot be 1.

Alternate Solution:

If a = 1, we have:

(1 - b)/c = 1

1 - b = c

The original equation had c in the denominator, so we know that c cannot equal 0. The value of b that makes c = 0 is b = 1. Thus, b cannot equal 1.

Answer: D
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If a = 1 and (a - b)/c = 1 which of the following is NOT a possible va 17 Dec 2024, 05:19
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Bunuel

Can we think this way that, since a-b=c or 1-b=c
then, 1-c=b or \(1-c/b=1\)

Since division by 0 is not defined value of b can't be zero?
Bunuel
imhimanshu
Hi.
Can anyone let me know what is wrong in my approach -

(a-b)/c = 1

a-b = c(by cross multiplying)
Now as a= 1
1-b = c
implies, 1-c=b
Now c can take any value, and b can have any of the values provided in the answer choices. Please let me know where I am going wrong. Why it is not possible to cross multiply in the first instance. this is how I approached in my exam.

Thanks

If a=1 and (a-b)/c = 1 which of the following is NOT a possible value of b?
A. -2
B. -1
C. 0
D. 1
E. 2

First of all remember that division by zero is undefined, hence \(c\neq{0}\) and that's why you CAN cross-multiply.

\(\frac{a-b}{c}=1\) --> as \(a=1\) --> \(\frac{1-b}{c}=1\) --> \(1-b=c\), but since \(c\neq{0}\), then \(1-b\neq{0}\) --> \(b\neq{1}\).

Answer: D.

Hope it's clear.
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Bunuel
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If a = 1 and (a - b)/c = 1 which of the following is NOT a possible va 17 Dec 2024, 08:44
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nishantswaft
Bunuel

Can we think this way that, since a-b=c or 1-b=c
then, 1-c=b or \(1-c/b=1\)

Since division by 0 is not defined value of b can't be zero?
Bunuel
imhimanshu
Hi.
Can anyone let me know what is wrong in my approach -

(a-b)/c = 1

a-b = c(by cross multiplying)
Now as a= 1
1-b = c
implies, 1-c=b
Now c can take any value, and b can have any of the values provided in the answer choices. Please let me know where I am going wrong. Why it is not possible to cross multiply in the first instance. this is how I approached in my exam.

Thanks

If a=1 and (a-b)/c = 1 which of the following is NOT a possible value of b?
A. -2
B. -1
C. 0
D. 1
E. 2

First of all remember that division by zero is undefined, hence \(c\neq{0}\) and that's why you CAN cross-multiply.

\(\frac{a-b}{c}=1\) --> as \(a=1\) --> \(\frac{1-b}{c}=1\) --> \(1-b=c\), but since \(c\neq{0}\), then \(1-b\neq{0}\) --> \(b\neq{1}\).

Answer: D.

Hope it's clear.


No. b could be 0. For example, a = 1, b = 0, and c = 1. When from 1 - c = b, you divide by 0, you are already violating the division by 0 rule by dividing by b, which could be 0.
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