Register To Attempt Complete Test
Michael Johnson is a great sprinter. He can climb 12 stairs of a staircase in 3 s. But after climbing 480 stairs his speed reduces to 8 stairs in 3 s. The empire state building in NY has 90 floors and the lift takes 4 s per floor. To get to the next floor one has to climb 12 stairs. If Michael is on the ground floor how should he reach the 90th floor to be the first?