There were some red and green pens in box X and box Y. There were 90 more pens in box Y than box X. The number of red pens in box Y was 30 more than the number of red pens in box X. In box X, there were 25 more green pens than red pens. How many more green pens than red pens were there in box Y?

1. Find the difference in the number of green pens between Box Y and Box X.

Since Box Y has $90$ more pens in total than Box X, and $30$ more red pens than Box X, the number of extra green pens in Box Y compared to Box X is:
$90 - 30 = 60$

2. Calculate how many more green pens than red pens there are in Box Y.

In Box X, there are $25$ more green pens than red pens.
In Box Y, the number of green pens increased by $60$ (relative to Box X) and the number of red pens increased by $30$ (relative to Box X).
The new difference between green and red pens in Box Y is:
$25 + 60 - 30 = 55$