wu :: forums - Print Page


    
      
        wu :: forums
        (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi)
      

        riddles >> easy >> Autistic chap
        
(Message started by: alien on Mar 7^th, 2005, 9:16am)

Title: Autistic chap
Post by alien on Mar 7^th, 2005, 9:16am

You are autistic, and there are 90 stairs you have to climb. When will you reach the last, 90th stair, if you need just one second to step on the first stair, then for each next stair it takes a second more (2 secs for the second stair, three for the third, and so on)?

Title: Re: Autistic chap
Post by Three Hands on Mar 7^th, 2005, 10:02am

4095s, or 1 hour, 8 minutes and 15 seconds

Title: Re: Autistic chap
Post by alien on Mar 7^th, 2005, 11:36am

Yes. :)

Title: Re: Autistic chap
Post by Grimbal on Mar 7^th, 2005, 3:24pm

Glad to see you solved that one in less than 1 hour and 8 minutes ;D

Title: Re: Autistic chap
Post by Lalamel on Mar 9^th, 2005, 6:02am

or, be practical and use the elevator... therefore, 1 sec to get into the elevator + time to get up there (depending on the elevator) + 1 sec to get out of the elevator (not 2 secs because you had some rest while in elevator)... so, it could be 2s + t, and the t can be determined emphirically, or contact the elevator manufacturer for further detail.

and - forgot to give the time it takes you to get from the stairway to the location of the elevator... my buiding - 1 sec x 2, so we get:

4s + t

as the final formula. ;D