Jim starts climbing up a tree to get a mango 30 feet away.

Question

In the first minute he climbs 3 feet, but in the next minute he slips down 1 foot. He again climbs 3 feet in the next minute and slips down 1 foot in the next. This goes on until he gets to the mango.

How long does it take him to get to the mango.

A. 15 minutes

B. 18 minutes

C. 24 minutes

D. 29 minutes

E. 30 minutes

Leon0973 · Accepted Answer

Jim climbs an average of 2ft every 2 minutes.

Therefore, 28ft / 2 = 14

14 x 2 minutes = 28 minutes. The final 1 minute Jim climbs 3 feet and reaches a height of 31ft.

Therefore the answer is 29 minutes.

Answer Choice: D

magbot · Answer

I think answer A - 15min

up and down, it takes 2mins for 2ft.

at 14 mins he would have climbed 28 ft
15th min - he would have reached the top

Abhishek009 · Answer

Jim climbs 2 foot in 2 minutes...

Thus, to climb 30 foot he requires 30/2 = 15 minutes, Answer must be (A)

apK98 · Answer

Can someone please explain why its not 30 minutes??

CrackverbalGMAT · Answer

Hi apk98. It is given that Jim climbs 3 feet in 1 minute and slips down a foot in the next.

So every 2 minutes, he climbs 2 feet.

Here comes the twist. When he reaches 28 feet, he has taken 28 minutes and the last action was that he had slipped. His next action in the 29th minute would be to climb 2 m and since he climbs 3 m in the next minute, he would reach the mango in the 29th minute.

Hence  Option D

Arun Kumar

Regor60 · Answer

Write out a few of the series and you can see that at the end of every even minute the monkey has reached that same number in feet after sliding back 1 foot. 2/2, 16/16, etc.

So at the end of 28 minutes he has slid back 1 foot from 29 feet to 28 feet.

So in the 29th minute he will progress up another 3 feet to meet the top with 1 foot to spare

Posted from my mobile device

Kinshook · Answer

Given: Jim starts climbing up a tree to get a mango 30 feet away.

In the first minute he climbs 3 feet, but in the next minute he slips down 1 foot. He again climbs 3 feet in the next minute and slips down 1 foot in the next. This goes on until he gets to the mango.

Asked: How long does it take him to get to the mango.

The height reached by Jim in feet = 3 -1 + 3 - 1 + 3 - 1 + ...3 >= 30
30 = 2*14 + 2

In every 2 minutes Jim climbs = 3 - 1 = 2 feet

Time required to get the mango = 2*14 + 1 = 29 minutes

IMO D

brianfischer · Answer

Minute 1: +3
Minute 2: -1  
Minute 3: +3  
Minute 4: -1  
Minute 5: +3

So on and so forth.

What I see is that on the odd minutes, it is always +2 above what the minute number is. At minute 27 he will be at 29ft and then at Minute 28, he'll be at 28ft. Therefore, at minute 29, he'll be at 31ft. Since he isn't going to drop back down after getting the mango, 29 minutes is the answer. D

onlymalapink · Answer

is there any plausible reason why anybody would not choose 15 in the exam

Regor60 · Answer

Well, even if pressed for time, the statement that he climbs 3 ft in the first minute and falls back 1 ft in the next minute indicates that he progresses 2 ft every 2 minutes or 1 ft per minute

Which would give a ballpark answer of 30 minutes

bumpbot · Answer

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Jim starts climbing up a tree to get a mango 30 feet away.

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