Answer: A) 88572 Explanation: 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.

Answer: C) 2029 Explanation: How to find the years which have the same Calendars :   Leap year calendar repeats every 28 years. Here 28 is distributed as 6 + 11 + 11.   Rules: a) If given year is at 1st position after Leap year then next repeated calendar year is Givenyear+6. b) If given year is at 2nd position after Leap year then next repeated calendar year is Givenyear+11. c) If given year is at 3rd position after Leap year then next repeated calendar year is Givenyear+11.   Now, the given year is 2018 We know that 2016 is a Leap year. 2016    2017    2018    2019  2020 Lp Y      1st     2nd      3rd     Lp Y   Here 2018 is at 2 nd position after the Leap year. According to rule b) the calendar of 2018 is repeated for the year is 2018 + 11 = 2029.

Answer: C) 1947 Explanation: Given 82.5% of 2360  82.5100 x 2360 = 0.825 x 2360 = 1947

Answer: A) 10 days Explanation: After 10 days, the remaining food would be sufficient for the 1000 students for 20 more days -->If 1000 more students are added, it shall be sufficient for only 10 days (as the no. of students is doubled, the days are halved).

Answer: A) 4:3 Explanation: Given 15% of x = 20% of y => 15x = 20y => x/y = 20/15 => x : y = 4 : 3

Answer: A) Rs. 4000 Explanation: Given ratio of initial investments = 72:43:65 = 105 : 40 : 36.  Let the initial investments be 105x, 40x and 36x.   ∴A:B:C = 105x×4 + 150100×105x×8 : 40x×12 : 36x×12                  = 1680x : 480x : 432x = 35 : 10 : 9.   Hence, B's share = 21600×1054 = Rs. 4000.

Answer: C) 7:45 in the next morning Explanation: We know that the time difference between India and USA is 9 hrs 30 min. India is 9:30 hrs ahead of USA. Time in India = 4:15 + 9:30 = 13:45 PM. Required Time after 18 hrs = 13:45 + 18 hrs = 7:45 AM.   Hence it is 7:45 AM on the next morning.

Answer: C) C Explanation: It is explicitly given that all the 4 black balls are different, all the 3 red balls are different and all the 5 blue balls are different. Hence this is a case where all are distinct objects.   Initially let's find out the number of ways in which we can select the black balls. Note that at least 1 black ball must be included in each selection.   Hence, we can select 1 black ball from 4 black ballsor 2 black balls from 4 black balls.or 3 black balls from 4 black balls.or 4 black balls from 4 black balls.   Hence, number of ways in which we can select the black balls   = 4C1 + 4C2 + 4C3 + 4C4= 24-1 ........(A)   Now let's find out the number of ways in which we can select the red balls. Note that at least 1 red ball must be included in each selection.   Hence, we can select 1 red ball from 3 red ballsor 2 red balls from 3 red ballsor 3 red balls from 3 red balls   Hence, number of ways in which we can select the red balls= 3C1 + 3C2 + 3C3=23-1........(B)   Hence, we can select 0 blue ball from 5 blue balls (i.e, do not select any blue ball. In this case, only black and red balls will be there)or 1 blue ball from 5 blue ballsor 2 blue balls from 5 blue ballsor 3 blue balls from 5 blue ballsor 4 blue balls from 5 blue ballsor 5 blue balls from 5 blue balls.   Hence, number of ways in which we can select the blue balls= 5C0 + 5C1 + 5C2 + … + 5C5= 25..............(C)   From (A), (B) and (C), required number of ways=  2524-123-1