Question: Two pipes P and Q can fill a cistern in 12 and 15 minutes respectively. Both are opened together, but at the end of 3 minutes the first is turned off. How much longer will the cistern take to fill?

• 1. 9 1/4 min
• 2. 11 1/4 min
• 3. 7 1/4 min
• 4. 8 1/2 min

Question: Two pipes A and B can separately fill a tank in 2 minutes and 15 minutes respectively. Both the pipes are opened together but 4 minutes after the start the pipe A is turned off. How much time will it take to fill the tank?

• 1. 9 min
• 2. 10 min
• 3. 11 min
• 4. 12 min

Question: Two pipes A and B can fill a cistern in 20 and 30 minutes respectively, and a third pipe C can empty it in 40 minutes. How long will it take to fill the cistern if all the three are opened at the same time?

• 1. 19 1/7 min
• 2. 15 1/7 min
• 3. 17 1/7 min
• 4. 7 1/7 min

Question: A boy has nine trousers and 12 shirts. In how many different ways can he select a trouser and a shirt?

• 1. 21
• 2. 12
• 3. 9
• 4. 108

Question: There are 30 people in a group. If all shake hands with one another , how many handshakes are possible?

• 1. 870
• 2. 435
• 3. 30!
• 4. 29! + 1

Question: In how many different ways can the letters of the word ‘OPTICAL’ be arranged so that the vowels always come together?

• 1. 120
• 2. 720
• 3. 4320
• 4. 2160

Question: In how many different ways can the letters of the word ‘MATHEMATICS’ be arranged so that the vowels always come together?

• 1. 10080
• 2. 4989600
• 3. 120960
• 4. None of these

Question: How many 4-letter words with or without meaning, can be formed out of the letters of the word, ‘LOGARITHMS’, if repetition of letters is not allowed?

• 1. 40
• 2. 400
• 3. 5040
• 4. 2520

Question: In how many ways can a group of 5 men and 2 women be made out of a total of 7 men and 3 women?

• 1. 63
• 2. 90
• 3. 126
• 4. 45

Question: In how many different ways can four books A, B, C and D be arranged one above another in a vertical order such that the books A and B are never in continuous position?

• 1. 9
• 2. 12
• 3. 14
• 4. 18