GMAT CAT Quant exam 5 #12

[sanyu4]

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?

Please explain the answer using an example with integers instead. I find the explanation with the exponents confusing.

thank you,

[tim]

no. the numbers are too large to use integers. if you are going to understand the question, and more importantly if you are going to understand the general principle that will apply to other questions, you must accept and understand the exponents solution. if you can describe what was difficult for you about this solution, perhaps we can help you understand it better..