Flight of Stairs Question

There were 2 identical flights of steps. Charles walked up the first flight of steps and ran up the last 8 steps. He took a total of 82 seconds to reach the top of the first flight of steps.

He then walked up the second flight of steps and ran up the last 15 steps. He took a total of 54 seconds to reach the top of the second flight of steps.

His walking speed of both flights of steps was also the same. If Charlie was to walk up all the steps, how much time would he take to reach the top of one flight of steps?

Flight 1: walk + run 8 = 82 seconds
Flight 2: walk (less 7 steps) + run 15 = 54 seconds

7 extra steps walked --> 28 extra seconds
1 extra step walked --> 4 extra seconds

Using Flight 1, convert the 8 steps from run to walk
8 steps converted to walk --> 8 x 4 extra seconds = 32 extra seconds

Flight 1: Walk + 8more walk --> 82 + 32 = 114 seconds