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 
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

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 
Option: C Explanation : Click on Discuss to view users comments. 
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 
Option: C Explanation :
There are four choices for Mathematics and five choices for English. Click on Discuss to view users comments. 
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.  10^{2} 
B.  1023 
C.  2^{10} 
D.  10! 
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
