GRE Questions

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Given a secret is told to 3 persons in 3 minutes.
And if the process continues with each person saying 3 other persons,
In 30 minutes => the rocess for 10 times because each person time is 3 minutes.
Required number of persons = 3 + 32 + 33 + .... + 39 + 310

Now it forms a geometric progression,

Sum to n terms is S = arn - 1r - 1

Here a = 3, r = 3

 
=> 59048 x 3 /2

= 88572.

For 1 hour, 20 minutes is slower, then for
06 miuntes - 2 minutes is slower
30 minutes - 10 minutes
Actual time | false time
12 12
01 PM 12:40 PM (20 minutes slower)
02 PM 01:20 PM
03 PM 02:00 PM

So, when actual time is 3pm, the false time is 2 pm.
So, it loses 60 minutes when it shows 2 pm.

Duge Beipanjiang Bridge in southwest China, opened to traffic this week and now the highest bridge in the world, some 565 metres (1,854 feet) above the valley below.The bridge stretches across a 1,341-metre (4,400-foot) span. Three years in the making, it's estimated to have cost the Chinese government around 1 billion yuan (or US$144 million).The bridge is going to cut travel times between Liupanshui in the Guizhou province and Xuanwei in the Yunnan province to two hours instead of the current five – as long as you don't mind the heights.The bridge crosses the the Nizhu river, and to give you some idea of the size of the drop down to the water below, it's almost 2 Eiffel Towers or one-and-a-half Empire State Buildings.

Boxing is played in the ring whereas Wrestling is played in Arena.

Here, S = {1, 2, 3, 4, ...., 19, 20}=> n(s) = 20
Let E = event of getting a multiple of 4 or 15
=multiples od 4 are {4, 8, 12, 16, 20}
And multiples of 15 means multiples of 3 and 5
= {3, 6 , 9, 12, 15, 18, 5, 10, 15, 20}.
= the common multiple is only (15).
=> E = n(E)= 6
Required Probability = P(E) = n(E)/n(S) = 6/20 = 3/10.

Nothing can be deduced regarding the effect of reapirs of office building on efficency of workers,or the requirement of funds for repairs,from the given statement.So,neither 1 nor 2 is true