Answer: Dr. Bolton was born in 1926.
Work:
Let x be the thousands digit. So, you will have the tens digit be 2x, the ones digit be 6x, and the hundreds digit be 9x. Now, let's try x as 1. Then, you will have the thousands digit be 1, the tens digit be 2, the ones digit be 6, and the hundreds digit be 9. Hope it helps!