Jim filled his dog's bowl with 80 dog food pellets. Starting

Question

Jim filled his dog's bowl with 80 dog food pellets. Starting at 8:00 a.m., Jim's dog ate exactly once an hour, consuming exactly half of the number of dog food pellets remaining in the bowl at each feeding session. What percent of the original 80 pellets were there in the dog's bowl right before the dog began to eat at noon of the same day?

A. 2.75%
B. 3.125%
C. 6.25%
D. 12.5%
E. 20%

A. 2.75%
B. 3.125%
C. 6.25%
D. 12.5%
E. 20%

piwanowi · Accepted Answer

Can also just start with 1 since % at 12 pm is all we need. Start with 1 and divide in half every hour.

Amount at 8 AM: 1/1

9 AM: 1/2

10 AM: 1/4

11 AM: 1/8

12 PM: 1/16

1/16 = .0625 or 6.25%

Bunuel · Answer

The dog ate 4 times, at 8:00 a.m., 9:00 a.m., 10:00 a.m. and 11:00 a.m.

Each time, after eating, half of the pellets were left in the bowl than before, thus after 4 meals 80*1/2^4=5 pellets were left in the bowl.

5/80 is little more than 5%.

Answer: C.

arpithamouli · Answer

Ans C. At 8 AM -- 80 pellets were served eaten 40, at 9 am 40+80=120 were served, eaten 60.At 10am 60+80=140 were served eaten 70. At 11am, 70+80=150 were served eaten 75. remaining 80-75=5. 5/80*100=6.25

vishwash · Answer

thanks for a question that seems easy but is not in its own inherent way and one has to keep guard against such questions in gmat.. thanks also for the explanations provided and kudos for the provider

KarishmaB · Answer

The dog ate at 8:00, 9:00, 10:00 and 11:00.
It ate 40 + 20 + 10 + 5 = 75 pellets.

So % of pellets left = (5/80)*100 = 6.25%

Answer (C)

ScottTargetTestPrep · Answer

Solution:

At 8 am, the dog ate 40 pellets. At 9 am, the dog ate 20 pellets. At 10 am, the dog ate 10 pellets. At 11 am, the dog ate 5 pellets. Therefore, right before 12 pm, the dog has eaten 40 + 20 + 10 + 5 = 75 pellets and there are 5 pellets left in the bowl, which is 5/80 = 0.0625 = 6.25% of the original 80 pellets.

Answer: C

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Jim filled his dog's bowl with 80 dog food pellets. Starting

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