21.If 2x-y=4 then 6x-3y=?
(a)15                            (b)12                            (c)18                            (d)10

22.If x=y=2z and xyz=256 then what is the value of x?
(a)12                            (b)8                  (c)16                (d)6

23. (1/10)18 - (1/10)20 = ?
(a) 99/1020                  (b) 99/10          (c) 0.9              (d) none of these

24. Pipe A can fill in 20 minutes and Pipe B in 30 mins and Pipe C can empty the same in 40 mins.If all of them work together, find the time taken to fill the tank
(a) 17 1/7 mins            (b) 20 mins      (c) 8 mins        (d) none of these

25. Thirty men take 20 days to complete a job working 9 hours a day.How many hour a day should 40 men work to complete the job?
(a) 8 hrs                       (b) 7 1/2 hrs     (c) 7 hrs           (d) 9 hrs

26. Find the smallest number in a GP whose sum is 38 and product 1728
(a) 12                           (b) 20               (c) 8                 (d) none of these

27. A boat travels 20 kms upstream in 6 hrs and 18 kms downstream in 4 hrs.Find the speed of the boat in still water and the speed of the water current?
(a) 1/2 kmph                (b) 7/12 kmph  (c) 5 kmph       (d) none of these

28. A goat is tied to one corner of a square plot of side 12m by a rope 7m long.Find the area it can graze?
(a) 38.5 sq.m               (b) 155 sq.m    (c) 144 sq.m    (d) 19.25 sq.m

29. Mr. Shah decided to walk down the escalator of a tube station. He found   that if he walks down 26 steps, he requires 30 seconds to reach the bottom. However, if he steps down 34 stairs he would only require 18 seconds to get to the bottom. If the time is measured from the moment the top step begins   to descend to the time he steps off the last step at the bottom, find out the height of the stair way in steps?
a) 50 steps                   b)46 steps        c)47 steps        d)43 steps

30. The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member. Find how much younger is the new member ?
a) 40 years                   b) 35 years       c)42 years        d)46 years