Algebra exp - PS

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Algebra exp - PS

by karthikpandian19 » Wed Nov 16, 2011 6:23 pm
The function g is defined as follows. For any 3 digit integer (written xyz),
. If c and k are 3 digit integers, and , what is the value of c - k?

A. 400

B. 320

C. k/16c

D. 40

E. Cannot be determined

As an example, consider 325. .

We are given that f(c) = 16f(k). Let c be the integer lmn, and k be the integer pqr.





[spoiler]

That is, since 16 is a power of 2 (and not divisible by 3 or 5), the only difference between the 2 numbers must be in the first digit, the hundreds digit.

Since the tens' and ones' digits are the same, when we subtract, they will cancel out. (e.g. 353 - 153 = 200). l = p+4, so c must be four hundred greater than k.

Algebraically:

100l + 10m + k - (100p + 10q + r) = ? (We determined that m = q, and k = r, so those cancel.)

100l - 100p = ?

Substitute l = p + 4

100(p + 4) - 100p = 100p + 400 - 100p = 400.[/spoiler]
Cannot be determined.
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by karthikpandian19 » Tue Nov 22, 2011 10:15 pm
Can anyone explain this question?
karthikpandian19 wrote:The function g is defined as follows. For any 3 digit integer (written xyz),
. If c and k are 3 digit integers, and , what is the value of c - k?

A. 400

B. 320

C. k/16c

D. 40

E. Cannot be determined

As an example, consider 325. .

We are given that f(c) = 16f(k). Let c be the integer lmn, and k be the integer pqr.





[spoiler]

That is, since 16 is a power of 2 (and not divisible by 3 or 5), the only difference between the 2 numbers must be in the first digit, the hundreds digit.

Since the tens' and ones' digits are the same, when we subtract, they will cancel out. (e.g. 353 - 153 = 200). l = p+4, so c must be four hundred greater than k.

Algebraically:

100l + 10m + k - (100p + 10q + r) = ? (We determined that m = q, and k = r, so those cancel.)

100l - 100p = ?

Substitute l = p + 4

100(p + 4) - 100p = 100p + 400 - 100p = 400.[/spoiler]
Cannot be determined.

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by shankar.ashwin » Tue Nov 22, 2011 10:39 pm
Can you post the entire question? You haven't defined the function in the stem? Function(g) is defined as follows?