# Permutations and Combinations Questions - Permutation and Combinations

11:

If a five digit number divisible by 3 is to be formed using the numerals 0, 1, 2, 3, 4 and 5, without repetition, then total number of ways this can be done is

 A. 216 B. 240 C. 600 D. 3125 Answer Report Discuss Option: A Explanation : Click on Discuss to view users comments. berihun said: (6:26pm on Friday 5th May 2017) the answer i s " C "!! b/c 1st digit =5 ways 2nd digit=5ways 3rd digit =4 ways 4th=3 ways 5th digit =2 ways b/c repeatition is not allowd answer=5*5*4*3*2=600 Write your comments here:
12:

If sides AB, BC, CA of a triangle ABC have 3, 4 and 5 interior points respectively on them, then total number oftriangles that can be constructed by using these points as vertices, is

 A. 220 B. 204 C. 205 D. 195 Answer Report Discuss Option: C Explanation : Click on Discuss to view users comments. Write your comments here:
13:

A student can take one of four Mathematics sections and one of five English sections. The number n of ways he can register for the two courses, is

 A. 4 B. 5 C. 20 D. 30 Answer Report Discuss Option: C Explanation : There are four choices for Mathematics and five choices for English. n= 4 x 5= 20 Click on Discuss to view users comments. Write your comments here:
14:

There are 10 lamps in a hall. Each one of them can be switched on independently. The number of ways in which the hall can be illuminated is

 A. 102 B. 1023 C. 210 D. 10! Answer Report Discuss Option: B Explanation : Click on Discuss to view users comments. SASIKALA K said: (7:35am on Wednesday 21st February 2018) Total number of lamps =10Since at least one lamp is to be kept switched onThe total number of ways are10C1 10C2 ....10C1010C1 10C2 ....10C10⇒210−1⇒210−1⇒1024−1⇒1024−1⇒1023 Write your comments here:
15:

The number of ways in which 10 persons can sit around a circular table so that none of them has ~he same neighbours in any two aITangem~nts, is

 A. 9! B. C. 10! D. Answer Report Discuss Option: B Explanation : Click on Discuss to view users comments. Write your comments here: