Two pipes A and B can fill a tank in 10 and 20 minutes respectively.If both pipes are opened simultaneously,after how many minutes should pipe B be closed so that the tank is full in 8 minutes?
A. 3 min
B. 4 min
C. 2 min
D.5 min
Out of 8 crew members 3 particular members can sit only on the left side.Another 2 particular members can sit on the right side.Find the number of ways in which the crew can be arranged so that four men can sit on each side
Students attend our lectures, not because the mathematics we teach ‘makes lots of fun’ for us, but because they believe they can learn some essential knowledge from us. And each of our young students has only one life to live. We should therefore be a
H. Behnke
Mathematics is like checkers in being suitable for the young, not too difficult, amusing, and without peril to the state.