Three wheels can complete 40, 24 and 16 revolutions per minute respectively. There is a red spot on each wheel that touches the ground at time zero. After how much time, all these spots will simultaneously touch the ground again? `7 1/2` sec (b) `18\ s e c` (c) `7 1/2` min (d) `18` min

Three wheels can completed respectively 60, 36, 24 revolutions per minute . There is a red spot on each wheel that touches the ground at time zero . After how much time , all these spots will simultaneously touch the ground again ?

The radii of the front wheel and the rear wheel of a bike are 14 cm and 21 cm respectively. Rahul puts a red mark on the point of contact of each of the wheels with the ground when the bike is stationary. Once the bike start moving, then after what distance will the two red marks touch the ground again simultaneously? (a) 42 cm (b) 84 cm (c) 264 cm (d) 294 cm

Two pipes A and B can fill a tank in 18 minutes and 24 minutes respectively. If both the pipes are opened simultaneously, then after how much time should pipe B be closed so that the tank is full in 12 minutes?

Two pipes A and B can fill a tank in 24 minutes and 32 minutes respectively.If both the pipes are opened simultaneously,after how much time B should be closed so that eh tank is full in 18 minutes?

Two pipes A and B can fill a tank in 1 h and 75 min, respectively. There is also an outlet C. If all the three pipes are opened together. The tank is full in 50 min. How much time will be taken by C to empty the full tank?

Two pipes A and B can fill a cistern in 24 minutes and 30 minutes, respectively. There is also an outlet C. If all the three pipes are opened together, the cistern is filled in 20 minutes. How much time will be taken by C to empty the full cistern?

Two pipes A and B can fill a tank in 36 min and 45 min, respectively. A pipe 'C' can empty the tank in 30 min. If all the three pipes are opened simultaneously, then in how much time the tank will be completely filled?