Answer: B) 7 hrs Explanation: Given, P can fill in 12 hrs Q can fill in 15 hrs R can fill in 20 hrs => Volume of tank = LCM of 12, 15, 20 = 60 lit => P alone can fill the tank in 60/12 = 5 hrs => Q alone can fill the tank in 60/15 = 4 hrs => R alone can fill the tank in 60/20 = 3 hrs Tank can be filled in the way that (P+Q) + (P+R) + (P+Q) + (P+R) + .... => Tank filled in 2 hrs = (5+4) + (5+3) = 9 + 8 = 17 lit => In 6 hrs = 17 x 6/2 = 51 lit => In 7th hr = 51 + (5+4) = 51 + 9 = 60 lit => So, total tank will be filled in 7 hrs.

Answer: A) 9!/(2!)^{2}x3! Explanation: n items of which p are alike of one kind, q alike of the other, r alike of another kind and the remaining are distinct can be arranged in a row in n!/p!q!r! ways.The letter pattern 'MESMERISE' consists of 10 letters of which there are 2M's, 3E's, 2S's and 1I and 1R.Number of arrangements = 9!(2!)2×3!

Answer: C) Rs. 2160 Explanation: => 60x5 : 36x6 : 75x3 => 100 : 72 : 75 => 72/247 x 7410 = Rs. 2160

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: B) Half year Explanation: 3300 ----- 3% ↑ (1st time interval, 99) → 3399. Here, time interval is given as half-yearly i.e. 6 months.

Answer: A) 600 Explanation: Two men, three women and one child can be selected in ⁴C₂ x ⁶C₃ x ⁵C₁ ways = 600 ways.