Find the time taken by a worm to reach the top of the Tube measuring 30cm.

@systems (459)
India
January 3, 2009 1:53pm CST
A worm ascends 3cm during day and descends 2cm during night. How many days will the worm take to reach the top of the tube measuring 30cm ?
3 responses
Undertheoath
@Undertheoath (365)
• United States
3 Jan 09
Day 1: 3-2 = 1 HEIGHT Day 2: 4-2 = 2 cm Height Day 3: 5-2 = 3 cm HEIGHT Day 4: 6-2 = 4 cm Height Day 5: 7-2 = 5 cm Height Day 6: 8-2 = 6 cm Height Day 7: 9-2 = 7 cm Height Day 8: 10-2 = 8 cm Height Day 9: 11-2 = 9 cm height Day 10: 12-2 = 10 cm height ..... It'd take 28 days correct?
mano5chi
@mano5chi (207)
• Spain
3 Jan 09
Yeah, I think you are right. I made a mistake. In the 27th day the worm has ascended 27 cm, and when it ascends the 3cm of the 28th day it has reached to top. 28 days is the right answer, yeah!
systems
@systems (459)
• India
3 Jan 09
Good.. Thanks for the working part also.. My nice had asked me this question and I had answered 29 Days.. Later I calculated it as 28 Days.
Autumnrose2008
@Autumnrose2008 (1478)
• United States
3 Jan 09
lol 30 days. I hope I get it right.
systems
@systems (459)
• India
3 Jan 09
Unfortunately its a WRONG Answer.. I think you just multiplied 1cm with 30 cm.
mano5chi
@mano5chi (207)
• Spain
3 Jan 09
I think the answer is 29 days. The worm ascends 1cm per 24 hours (3cm up during day and 2cm down during night), so in 28 days it has ascended 28cm. Then the 29th day begins, and the worm ascends 3cm, so it has reached the top!. Right?