A school has 5 divisions in a class IX having 60, 50, 55, 62 and 58 students. Mean marks obtained in a History test were 56, 64, 72, 63 and 50 by each division respectively. What is overall average of the marks per students?
A.  56.8 
B.  58.2 
C.  62.4 
D.  60.8 
Option: D Explanation : Average = (60x56+50x64+55x72+62x63+58x50)/ (60+50+55+60+58 ) = (3360+3200+3960+3906+2900)/285 = 60.8 Click on Discuss to view users comments. 
What is the smallest number which when increased by 3 is divisible by 27, 35, 25 and 21?
A.  4722 
B.  4725 
C.  4728 
D.  4731 
Option: A Explanation : L.C.M. of 27, 35, 25 and 21 = 4725 ∴ Number = 47253 = 4722. Click on Discuss to view users comments. 
Which of the following is true?
A.  Sum of four consecutive even numbers is always divisible by 8. 
B.  Sum of four consecutive odd numbers is always divisible by 8. 
C.  Product of any n consecutive natural numbers may not be divisible by n!. 
D.  Product of 4 consecutive odd numbers is always divisible by 15. 
Option: B Explanation :
(A) Four consecutive even numbers can be written as 2n, 2n + 2, 2n + 4 and 2n + 6,where n is any natural number. Click on Discuss to view users comments. 
Sum of all odd numbers up to 100 is
A.  5050 
B.  2500 
C.  2525 
D.  5000 
Option: B Explanation :
Given numbers are 1, 3, 5.....99. Click on Discuss to view users comments. 
If x+y+z=0,then x2/yx + y2/zx + z2/xy equal
A.  0 
B.  1 
C.  2 
D.  3 
Option: D Explanation :
x^{2}/yx + y^{2}/zx + z^{2}/xy Click on Discuss to view users comments. Devanshu said: (11:20am on Friday 1st July 2016)
Let x=2 y =1 z=1 then x y z=0 but RHS is  3?????Btw if x y z = 0 then x^3 y^3 z^3=3xyz???? I think it should be  3xyz then ans satisfied
