Answer: 144
Step-by-step explanation:
The binomial is 
The expansion of 
Expansion of 

So, the second term is

Its Coefficient is

10x +y = xy +26
There are thee (3) sets of numbers that satisfy this.
.. (x, y) = (3, 2) . . . . the number is 32
.. (x, y) = (5, 6) . . . . the number is 56
.. (x, y) = (9, 8) . . . . the number is 98
If you solve the equation for y, you get
.. y = 10 -16/(x -1)
so x-1 is a 1-digit factor of 16: 2, 4, 8. These give rise to the solutions above.
So is 4 floors / 10 seconds
If you have 60 seconds you can multiple 10 by 6 because 10×6=60
so you also have to multiple 4 by 6
4×6=24
and because it's descending it's 100-24= 76