Answer: A) 3/91 Explanation: In a circle of n different persons, the total number of arrangements possible = (n - 1)!Total number of arrangements = n(S) = (15 – 1)! = 14 !Taking three persons as a unit, total persons = 13 (in 4 units)Therefore no. of ways for these 13 persons to around the circular table = (13 - 1)! = 12!In any given unit, 3 particular person can sit in 3!. Hence total number of ways that any three person can sit =n(E) = 12! X 3!Therefore P (E) = probability of three persons sitting together = n(E) / n(S) = 12! X 3 ! / 14!= 12!x3x2 / 14x13x12! = 6/14x13 = 3/91

Answer: A) 120 Explanation: 1/15 + 1/12 + 1/R = 1/6, we got R = 60 (it means R will take 60 days to complete the work alone) so ratio of work done by P:Q:R = 1/15 : 1/12 : 1/60 = 5 : 4 : 1 so R share = (1/10) x 1200 = 120.

Answer: D) 30 min Explanation: Part filled by (A + B) in 1 minute = (1/60 + 1/40) = 1/24Suppose the tank is filled in x minutes.Then, x/2(1/24 + 1/40) = 1(x/2) * (1/15) = 1 => x = 30 min.

Answer: B) 13 + 1/3 days Explanation: C alone can finish the work in 40 days.As given C does half as much work as A and B together => (A + B) can do it in 20 days(A + B)s 1 days wok = 1/20.A's 1 days work : B's 1 days Work = 1/2 : 1 = 1:2(given)A's 1 day’s work = (1/20) x (1/3) = (1/60) [Divide 1/20 in the raio 1:2]B's 1 days work = (1/20) x (2/3) = 1/30(A+B+C)'s 1 day's work = (1/60) + (1/30) + (1/40) = 9/120 = 3/40 All the three together will finish it in 40/3 = 13 and 1/3 days.

Answer: A) 48 Explanation: 3X + 4y = 240by substitute through options 48 is correct

Answer: B) 20th April, Saturday Explanation: Given Today is 20th January 2017, Sunday In january, we have 31 days February - 28 days (Non leap year) March - 31 days April - 30 days => Remaining days => 31 - 20 = 11 in Jan + 28 in Feb + 31 in Mar = 11 + 28 + 31 = 70 days More 20 days to complete 90 days => upto 20th April   Therefore, after 90 days from today i.e, 20th Jan 2017 is 20th Apr 2017.   Now, the day of the week will be  90/7 => Remainder '6' As the day starts with '0' on sunday  6 => Saturday.   Required day is 20th April, Saturday.