His mother will be 40 in 8 years. So, she is 32 now.
1/8 of his mother's age is 4, so, currently Jaden is 4 years old.
The difference are 28 years.
If he is currently 4 in 17 years he will be 21 years old and his mother will be 49,
21 is 3/7 of 49.
Therefore, the correct answer is, in 17 years.
