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The operation delta is defined for all nonzero x and y b x

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The operation delta is defined for all nonzero x and y b x  [#permalink]

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New post Updated on: 03 Jan 2014, 05:03
3
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A
B
C
D
E

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The operation # is defined for all nonzero x and y by x#y = x + x/y. If a>0, then 1#(1#a) =

A. a
B. a+1
C. a/(a+1)
D. (a+2)/(a+1)
E. (2a+1)/(a+1)

OPEN DISCUSSION OF THIS QUESTION IS HERE: the-operation-is-defined-for-all-nonzero-x-and-y-by-x-y-162019.html

Originally posted by nfa1rhp on 29 Jul 2007, 11:56.
Last edited by Bunuel on 03 Jan 2014, 05:03, edited 1 time in total.
Renamed the topic, edited the question, added the OA and moved to PS forum.
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New post 29 Jul 2007, 13:53
(E) for me :)

o 1 delta a
= 1 + 1/a
= (a + 1)/a

o 1 delta (1 delta a)
= 1 delta ((a + 1)/a)
= 1 + 1/((a + 1)/a)
= 1 + a/(a+1)
= (2*a + 1) / (a + 1)
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New post 30 Jul 2007, 23:39
1 delta a = 1 + 1/a
Let 1 delta a be x

Then 1 delta (1 delta a) = 1 delta x = 1 + 1/x. Subsitute in x, to give

1 + 1/(1+1/a) = 1 + a/(a+1) = a+1+a/(a+1) = 2a+1/(a+1)
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Re: The operation delta is defined for all nonzero x and y b x  [#permalink]

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New post 02 Jan 2014, 08:26
Can someone explain the math better on this one? Brunnel, do you mind?
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Re: The operation delta is defined for all nonzero x and y b x  [#permalink]

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New post 03 Jan 2014, 05:04
jeremyl3763 wrote:
Can someone explain the math better on this one? Brunnel, do you mind?


The operation # is defined for all nonzero x and y by x#y = x + x/y. If a>0, then 1#(1#a) =
A. a
B. a+1
C. a/(a+1)
D. (a+2)/(a+1)
E. (2a+1)/(a+1)

\(1#(1#a) = 1#(1+\frac{1}{a}) = 1#(\frac{a+1}{a})= 1+ \frac{1}{(\frac{a+1}{a})}=1+\frac{a}{a+1}=\frac{a+1+a}{a+1}=\frac{2a+1}{a+1}\).

Answer: E.

OPEN DISCUSSION OF THIS QUESTION IS HERE: the-operation-is-defined-for-all-nonzero-x-and-y-by-x-y-162019.html
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Re: The operation delta is defined for all nonzero x and y b x  [#permalink]

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New post 03 Jan 2014, 05:04
1
Bunuel wrote:
jeremyl3763 wrote:
Can someone explain the math better on this one? Brunnel, do you mind?


The operation # is defined for all nonzero x and y by x#y = x + x/y. If a>0, then 1#(1#a) =
A. a
B. a+1
C. a/(a+1)
D. (a+2)/(a+1)
E. (2a+1)/(a+1)

\(1#(1#a) = 1#(1+\frac{1}{a}) = 1#(\frac{a+1}{a})= 1+ \frac{1}{(\frac{a+1}{a})}=1+\frac{a}{a+1}=\frac{a+1+a}{a+1}=\frac{2a+1}{a+1}\).

Answer: E.

OPEN DISCUSSION OF THIS QUESTION IS HERE: the-operation-is-defined-for-all-nonzero-x-and-y-by-x-y-162019.html


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Hope this helps.
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Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

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Re: The operation delta is defined for all nonzero x and y b x  [#permalink]

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New post 04 Aug 2018, 05:39
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Re: The operation delta is defined for all nonzero x and y b x &nbs [#permalink] 04 Aug 2018, 05:39
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