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by euro » Fri Nov 12, 2010 11:16 am
rishi.riddle wrote:I have attached a question and in it ans is also there. But give the explanation
Given that A, B, C and D are equally spaced.

Distance between D and C:
= D - C
= 5^13 - 5^12
= 5^12 (5-1)
= 4 x 5^12
This distance will remain constant between A & B and B & C.

Therefore value of A
= Value of C - 2 x [Distance]
= 5^12 - 2 [4 x 5^12]
= 5^12 - 8 x 5^12
= 5^12 (1 - 8)
= 5^12 (-7)

Correct Answer is D
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by Rahul@gurome » Fri Nov 12, 2010 11:21 am
The integers A, B, C, and D shown on the number line above are all equally spaced. If C and D are equal to 5^12 and 5^13, respectively, what is the value of A?

Distance between C and D = 5^13 - 5^12 = (5^12)*(5 - 1) = 4*(5^12)
Distance between A and B = Distance between B and C = Distance between C and D = 4*(5^12)

Distance between A and D = Distance between A and B + Distance between B and C + Distance between C and D = 4*(5^12) + 4*(5^12) + 4*(5^12) = 3*4*(5^12) = 12*(5^12)

D = 5^13
Therefore, A = D - Distance between A and D = 5^13 - 12*(5^12) = (5^12)*(5 - 12) = (-7)*(5^12)

The correct answer is D.
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by rishi.riddle » Fri Nov 12, 2010 11:53 am
thkx rahul for good explanation........... the explanation i was looking for.......
Rahul@gurome wrote:The integers A, B, C, and D shown on the number line above are all equally spaced. If C and D are equal to 5^12 and 5^13, respectively, what is the value of A?

Distance between C and D = 5^13 - 5^12 = (5^12)*(5 - 1) = 4*(5^12)
Distance between A and B = Distance between B and C = Distance between C and D = 4*(5^12)

Distance between A and D = Distance between A and B + Distance between B and C + Distance between C and D = 4*(5^12) + 4*(5^12) + 4*(5^12) = 3*4*(5^12) = 12*(5^12)

D = 5^13
Therefore, A = D - Distance between A and D = 5^13 - 12*(5^12) = (5^12)*(5 - 12) = (-7)*(5^12)

The correct answer is D.
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