To solve this question, we need to translate Uncle Grandpa's statement into a mathematical equation. When he says "40 less than my age double," he's describing twice of his own age minus 40. If we set that equal to "his" age, which we'll call x, we get a straightforward equation to solve:
2x - 40 = x where x represents "his" age.
In order to solve this equation, we need to get x by itself on one side of the equation.
This can be accomplished by adding 40 to each side of the equation to get:
2x - 40 + 40 = x + 40 which simplifies to
2x = x + 40
Then, to isolate x, we can subtract x from each side of the equation to get:
2x - x = x + 40 - x which simplifies to
x = 40
So, the answer to the question, "how old is 'his' age" will be 40 years old. This corresponds to option (B).
Answer: B) 40