Question

In the 99-story house there is an elevator with two buttons only. If you click on the first button, you will go 7 floors up, if you click on the second one then you go 9 floors down. How can you get from the first floor to the 72nd?

Answer 1

to get from the first floor to the 72nd, the person need to click 14 times the first button to get the floor 99nd and then click 3 times the second button to get the floor 72nd

Explanation:

if the person is on the first floor and he click the first button 14 times, he will be on the floor 99nd because, 1+(14*7) = 99, and if he click the second button 3 times then will be on the 72nd floor because, 99-(3*9) = 99-27 = 72