Click to Get updated NTA UGC NET CS Test Series           Study Material for UGC NET Computer Science- 2019

# Numbers & Algebra - Numbers and Algebra MCQ

21:

If x+y+z=0,then x2/yx + y2/zx + z2/xy equal

 A. 0 B. 1 C. 2 D. 3 Answer Report Discuss Option: D Explanation : x2/yx + y2/zx + z2/xy              ...(since, x+y+z=0  'x3+y3+z3=3xyz) (x3+y3+z3) / xyz = 3xyz / xyz = 3. Click on Discuss to view users comments. Devanshu said: (4:20am 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 Write your comments here:
22:

Average age of a committee of seven trustees is the same as it was five years ago, a younger man having been substituted for one of them. How much younger was he then trustee whose place he took?

 A. 32 years B. 35 years C. 33 years D. 34 years Answer Report Discuss Option: B Explanation : Increase after 5 years should have been 7 x 5 = 35 years. But since average remains same, diference in their age is 35 years. Click on Discuss to view users comments. Write your comments here:
23:

What is the least number which must be subtracted from 1936 so that the remainder when divided by 9, 10, 15 will leave in each case the same remainder 7?

 A. 32 B. 53 C. 46 D. 39 Answer Report Discuss Option: D Explanation : L.C.M. of 9, 10 and 15 = 90 ∴ 1936 = 90 x 21 + 46 (Remainder). But a part of this remainder is 7. 39 should be subtracted from 1936. Click on Discuss to view users comments. nidhi said: (5:20pm on Wednesday 19th August 2015) from where 9x21 46 comeshow 39 is the right answer sudeep said: (5:53pm on Monday 28th November 2016) L.C.M of 9,10,15=901936÷90=21. and remainder 46.but remainder is always 7,so 46-7=39. Write your comments here:
24:

What is the maximum sum of the series 60, 58, 56, 54, 52, ?

 A. 840 B. 880 C. 930 D. 1120 Answer Report Discuss Option: C Explanation : Since d = -2, maximum sum of the series will be sum of all the positive terms. Least positive term of the series is 2 or 0 (both giving equal sum) Let, 2 be the nth term 2 = 60 + (n 1) - 2  => n = 30 Required sum = 30/2 (60 + 2) = 930 Click on Discuss to view users comments. Write your comments here:
25:

What is the least number which on being divided by 12, 21 and 35 will leave in each case the same remainder 6?

 A. 210 B. 414 C. 420 D. 426 Answer Report Discuss Option: D Explanation : L.C.M. of 12, 21 and 35 = 420  ∴ Number required = 420 + 6 = 426 Click on Discuss to view users comments. Write your comments here:

## Suggest an improvement X