Originally Posted by

**mjoshua** On a number line, tick marks are spaced so that the distance from a to b is twice the distance from b to c and the distance from b to c is twice the distance from c to d. If a, b, c, and d are positive integers, what is the smallest possible value of d?

How can we show that it is 8?

Could it be that you didn't mention that a < b < c < d ?

Since the distance is a scalar (and not a vector) the ticks could be arranged: Code:

0--1--2--3--4--5\\
---a--d--c-----b

In this case the smallest value of d = 2.

Maybe there other arrangement possible (?)