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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