21) If P, Q and R work together, they take 12 days to complete the work. However, if only P and R work, they take 20 days to complete the work. A schedule is made such that P and R work every day, while Q joins them only on alternate days i.e. on 1st, 3rd, 5th, 7th, … days. On which day will the work be completed?
A) 15th
B) 14th
C) 13th
D) 17th
22) A train running at the speed of 72 km/hr can cross a stationary pole in 10 seconds. How much time will it take to overtake a train of length 500 metres running at 54 km/hr in the same direction?
A) 130 seconds
B) 110 seconds
C) 120 seconds
D) 140 seconds
23) In a class with 20 students, the average score in a test is 15. Out of the 20 students, 5 students scored 0 mark. What is the average marks of the remaining student if the students who scored 0 mark are excluded?
A) 18
B) 22
C) 20
D) 16
24) 12 men and 6 women can complete a work in 10 days. 3 men and 6 women can complete this work in 25 days. How many men are required to complete this work in 5 days?
A) 30
B) 20
C) 24
D) 36