# Need Answers of these 2 MCQS with some sort of explanation....plz

• Sep 21st 2011, 10:54 PM
nasir31971
Need Answers of these 2 MCQS with some sort of explanation....plz
Q1. How many ways can 5 people be lined up to get a bus if a certain 3 persons insist on following each other?

a. 20 b. 36 c. 120 d. 360

Q2. A town has 2 fire engineers operating independently.The prbability that a specific fire engine is available when needed is 0.95. What is the prbability that neither is available when needed?

a. 0.0025 b. 0.05 c. 0.10 d. 0.25
• Sep 21st 2011, 11:30 PM
arangu1508
Re: Need Answers of these 2 MCQS with some sort of explanation....plz
Q.1. I feel you have to take the 3 persons as a block. Then 5 people will be reduced as 3 people. This can be arranged in 6 ways. Similarly, we considered 3 persons as a block. In the block, the 3 persons can be arranged in 6 ways. Hence, I feel it should be 6 x 6 = 36.
• Sep 21st 2011, 11:36 PM
arangu1508
Re: Need Answers of these 2 MCQS with some sort of explanation....plz
For the second one, I feel the probability for non-availability of a fire engine is 1-0.95 = 0.05. Both the engines are not available; hence 0.05 x 0.05 = 0.0025
• Sep 22nd 2011, 12:01 AM
nasir31971
Re: Need Answers of these 2 MCQS with some sort of explanation....plz
Thanks...