Find the average of the first 25 natural numbers?
Options:
(A) 8
(B) 9
(C) 13
(D) 11
(E) 12
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Average of the first 'n' natural numbers = (n + 1)/2
We get (25 + 1)/2 = 13 So the answer is: (C).
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A man purchased 2 blankets @ Rs.100 each, 5 blankets @ Rs.150 each and two blankets at a certain rate which is now slipped off from his memory. But he remembers that the average price of the blankets was Rs.150. Find the unknown rate of two blankets?
Options:
(A) 278
(B) 277
(C) 278
(D) 450
(E) 550
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10 * 150 = 1500
2 * 100 + 5 * 150 = 950
1500 – 1050 = 550 So the answer is: (E).
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Joey is planning to throw a small party and for that he needs to do the following tasks:
I. Decide guest list
II. Send invites
III. Arrange catering
IV. Decide the venue
V. Rent a music system
The tasks can be done in any order as long as the invites are sent after the guest list is decided. In how many ways can Joey do the five tasks listed above?
Options:
(A) 24
(B) 48
(C) 60
(D) 120
(E) 240
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Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
These 5 tasks can be arranged in 5! = 120 ways. In half of them invites are sentafterthe guest list is decided and in half of them before. So, there are total of 120/2 = 60 ways to arrange the task so that the invites are sent after the guest list is decided. So the answer is: (C).
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