7. (6 points) Xiaopang needs 90 seconds to go from the first floor to the third floor. At this speed, it would take him $\qquad$ seconds to go from the second floor to the seventh floor.
7. (6 points) Xiaopang needs 90 seconds to go from the first floor to the third floor. At this speed, it takes him 225 seconds to go from the second floor to the seventh floor.
【Solution】Solution:
The time to climb each floor is: $90 \div(3-1)=45$ (seconds);
The time for him to go from the second floor to the seventh floor is: $45 \times(7-2)=225$ (seconds).
Answer: It takes him 225 seconds to go from the second floor to the seventh floor.
Therefore, the answer is: 225.