Answer: (B)
Question: There are 1000 doors that are of the open-close type. When a person opens the door he closes it and then opens the other. When the first person goes he opens-closes the doors in the multiples of 1 i.e., he opens and closes all the doors. when the second goes he opens and closes the doors 2, 4 6 8 respectively. Similarly when the third one goes he does this for 3 6 9 12 15th doors respectively. Find number of doors that are open at last.
Options:
(A) 29
(B) 31
(C) 32
(D) 24
(E) 21
[CoT]: [31. only the perfect squares between 1 to 1k]

Answer: (B)
Question: Jamie's friend Bob is having a party, but Jamie forgot and went to dinner with her friend Emily instead. Bob's party starts in half an hour. Bob lives 30 km away from Jamie, and the restaurant Jamie and Emily are at is three times as far away from Bob's house as Jamie's house is.
How fast would Jamie have to drive in order to get to Bob's party on time?
Options:
(A) 30 km/h
(B) 45 km/h
(C) 60 km/h
(D) 75 km/h
(E) 90 km/h
[CoT]: [Distance between Bob's house and Jamie's restaurant: 30 x 3 = 90 km
Rate of speed to get to Bob's house in an hour: 90 x 1 = 90 km/h
Rate of speed to get to Bob's house in half an hour: 90/2 = 45 km/h]

Answer: (A)
Question: A women purchased 3 towels @ Rs.100 each, 5 towels @ Rs.150 each and two towels at a certain rate which is now slipped off from his memory. But she remembers that the average price of the towels was Rs.145. Find the unknown rate of two towels?
Options:
(A) A) 400
(B) B) 450
(C) C) 500
(D) D) 550
(E) E) 600
[CoT]: [10 * 145 = 1450
3 * 100 + 5 * 150 = 1050
1450 – 1050 = 400]

Answer: (A)
Question:

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
A 160 meter long train crosses a man standing on the platform in 12 sec. What is the speed of the train?
Options:
(A) 48 kmph
(B) 54 kmph
(C) 92 kmph
(D) 86 kmph
(E) 76 kmph
[CoT]: [S = 160/12 * 18/5 = 48 kmph]