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netcaesar
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A geyser spouts at regular intervals. Will it spout more 24 Jan 2008, 16:00
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A geyser spouts at regular intervals. Will it spout more than 18 times in the seven day period beginning tonight at midnight?

1) It spouted 3 times yesterday´
2) It spouted 3 times the day before yesterday



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A geyser spouts at regular intervals. Will it spout more 24 Jan 2008, 16:54
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A wild guess, but I would say E. Because you still do not know the intervals at which it sprouts.
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A geyser spouts at regular intervals. Will it spout more 24 Jan 2008, 19:37
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netcaesar
A geyser spouts at regular intervals. Will it spout more than 18 times in the seven day period beginning tonight at midnight?

1) It spouted 3 times yesterday´
2) It spouted 3 times the day before yesterday
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1. insufficient, information of spouting in one day is not reflect that geyser spouts day by day

2. insufficient, the same reason

1 and 2 combined is sufficient. 3*6 + 3/2 =19 1/2 intervals > 18

C
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A geyser spouts at regular intervals. Will it spout more 24 Jan 2008, 20:46
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sondenso
netcaesar
A geyser spouts at regular intervals. Will it spout more than 18 times in the seven day period beginning tonight at midnight?

1) It spouted 3 times yesterday´
2) It spouted 3 times the day before yesterday

1. insufficient, information of spouting in one day is not reflect that geyser spouts day by day

2. insufficient, the same reason

1 and 2 combined is sufficient. 3*6 + 3/2 =19 1/2 intervals > 18

C
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This seems ok, but why can't we have this scenario?

Day 1
Spout
Day 2
Spout
Day 3
No spout
Day 4
No spout
Day 5
Spout
Day 6
Spout


etc... the term regular intervals seems kinda flimsy to me.
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A geyser spouts at regular intervals. Will it spout more 25 Jan 2008, 09:48
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OA is E, but I do not understand the reasoning.

From I, we know that the time between 2 eruptions is less than 24 h/2= 12 h
For 7 days, that is 7*24= 168 hours, there will be more than 168/12 = 14 eruptions, but we do not know if there will be more than 18 eruptions.

From II, we know the same that from I: there willl be more than 14 eruptions.

But I do not how to do with both statements together!!!!
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A geyser spouts at regular intervals. Will it spout more 25 Jan 2008, 10:32
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E

t- interval between eruptions.

1. t_min=24/2=12; t_max=24/4=6; t e (6,12) ==> N e (7*24/12, 7*24/6) ==> N e (14,28) ==> N e [15,27] insufficient

2. the same as for 1.

1&2. t_min=48/5=9.6; t_max=48/7~6.8; t e (6.8,9.6) ==> N e (7*24*5/48, 7*24*7/48) ==> N e (17.5,24.5) ==> N e [18,24] insufficient



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This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
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