Question : A takes 2 hours 30 minutes more than B to walk 40 km. If A doubles his speed, then he can make it in 1 hour less than B. What is the average time taken by A and B to walk a 40 km distance?

Option 1: 7 hours 15 minutes

Option 2: 5 hours 45 minutes

Option 3: 6 hours

Option 4: 5 hours 15 minutes

Question : Two pipes A and B can fill a tank in 12 hours and 18 hours, respectively. Both pipes are opened simultaneously. In how much time will the empty tank be filled completely?

Option 1: 9 hours 30 minutes

Option 2: 8 hours

Option 3: 7 hours 12 minutes

Option 4: 10 hours 24 minutes

Question : Pipes A and B can fill a tank in 18 minutes and $22 \frac{1}{2}$ minutes, respectively while pipe C can empty the full tank in 12 minutes. A and B are opened together for 6 minutes and then closed. Now C is opened. C alone will empty the tank in ____.

Option 1: $5$ minutes

Option 2: $8 \frac{2}{5}$ minutes

Option 3: $7 \frac{1}{5}$ minutes

Option 4: $6$ minutes

Question : X can do a work in 3 days, Y can do three times the same work in 8 days, and Z can do five times the same work in 12 days. If they have to work together for 6 hours a day, then how much time will they take to complete the work?

Option 1: 4 hours

Option 2: 5 hours 20 minutes

Option 3: 4 hours 10 minutes

Option 4: 5 hours

Question : The ratio of the fifth and sixth terms of the sequence 1, 3, 6, 10, ..... is:

Option 1: $5:6$

Option 2: $5:7$

Option 3: $7:5$

Option 4: $6:5$