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Quantitative Aptitude

SURDS AND INDICES MCQs

Surds & Indices, Indices And Surds, Power

Total Questions : 753 | Page 26 of 76 pages
Question 251.

`(1000)^7 -:  10^18`    ?


  1.    10
  2.    100
  3.    1000
  4.    10000
 Discuss Question
Answer: Option C. -> 1000

`(1000)^7 -:  10^18` =  `(1000)^7/10^18`   =  `(10^3)^7/10^18` =  `10^((3 xx 7))/(10^18)`

=`10^21/10^18` = `(10)^(21 - 18)` =  `10^3` =  1000



Question 252.

`(1/216)^(- (2)/(3))  -:  (1/27)^(- (4)/(3)) ` =  ?


  1.    `3/4`
  2.    `2/3`
  3.    `4/9`
  4.    `1/8`
 Discuss Question
Answer: Option C. -> `4/9`

`(1/216)^(- (2)/(3))  -:  (1/27)^(- (4)/(3)) `   =  `(216)^(2/3)  -:  (27)^(4/3)`      = `((216)^(2/3))/((27)^(4/3))`

= `((6^3)^(2/3))/((3^3)^(4/3)`  = `(6^((3 xx 2/3)))/(3^((3 xx 4/3)))`   =  `(6^2)/(3^4)`=  `36/81` =  `4/9`



Question 253.

`(2.4 xx 10^3) -: (8 xx 10^-2)` = ?


  1.    `3 xx 10^-5`
  2.    `3 xx 10^4`
  3.    `3 xx 10^5`
  4.    30
 Discuss Question
Answer: Option B. -> `3 xx 10^4`

`(2.4 xx 10^3) -: (8 xx 10^-2)`= `(2.4 xx 10^3)/(8 xx 10^-2)` = `(24 xx 10^2)/(8 xx 10^-2)`   = `(3 xx 10^4)`


Question 254.

The value of` [(10)^150 -: (10)^146]`  is


  1.    1000
  2.    10000
  3.    100000
  4.    `10^6`
 Discuss Question
Answer: Option B. -> 10000

` (10)^150 -: (10)^146`   =  `((10)^150)/((10)^146)`     =   `(10)^(150 - 146)`     = `10^4` =  10000



Question 255.

The value of `(1)/((216)^(-  2/3)) + (1)/((256)^(-  3/4))  +(1)/((32)^(-  1/5)) ` is


  1.    102
  2.    105
  3.    107
  4.    109
 Discuss Question
Answer: Option A. -> 102

`(1)/((216)^(-  2/3)) + (1)/((256)^(-  3/4))  +(1)/((32)^(-  1/5)) `

  =`(1)/( (6^3)^( - 2/3))  + (1)/( (4^4)^( - 3/4))  + (1)/( (2^5)^( - 1/5)`

= `(1)/6^(3  xx  ( - 2)/3) +(1)/4^(4  xx (  - 3)/4) +(1)/2^(5  xx  (- 1)/5) `

=`(1)/(6)^-2 + (1)/(4)^-3 + (1)/(2)^-1`=  `(6^2 + 4^3 +2^1)` =  (36 +64 + 2) = 102.





Question 256.

The value of  `5^(1/4)  xx (125)^0.25`  is


  1.    `sqrt(5)`
  2.    5
  3.    `5sqrt(5)`
  4.    25
 Discuss Question
Answer: Option B. -> 5

`5^(1/4)  xx (125)^0.25`  =` 5^0.25 xx (5^3)^0.25` =  ` 5^0.25 xx 5^(3 xx 0.25)` = `5^0.25 xx 5^0.75`
= `5^((0.25 + 0.75))` = `5^1` = 5.




Question 257.

The value of `( - 1/216)^(  - (2)/(3))` is


  1.    36
  2.    - 36
  3.    `1/36`
  4.    `- 1/36`
 Discuss Question
Answer: Option A. -> 36

`( - 1/216)^(  - (2)/(3)) `=` [( - 1/6)^3] ^(- (2)/(3)`         = `(- 1/6)^(3 xx((-2))/(3))`     =  `(- 1/6)^ - 2`

= `1/(- 1/6)^2`       =  `1/(1/36)`     = 36.


Question 258.

The value of `(32/243)^(-  (4)/(5))`   is  :


  1.    `4/9`
  2.    `9/4`
  3.    `16/81`
  4.    `81/16`
 Discuss Question
Answer: Option D. -> `81/16`

`(32/243)^(-  (4)/(5))` =  `{(2/3)^5}^( - (4)/(5))`  = `((2)/(3))^(5 xx ((- 4))/(5))`  = `((2)/(3))^(- 4)`

= `(3/2)^4`    =`(3^4)/(2^4)`=    `81/16`



Question 259.

The value of `(sqrt(8))^((1)/(3))` is :


  1.    2
  2.    4
  3.    `sqrt(2)`
  4.    8
 Discuss Question
Answer: Option C. -> `sqrt(2)`

`(sqrt(8))^((1)/(3))` = `(8^(1/2))^((1)/(3))`        =  `8^((1/2 xx 1/3))`       = ` 8 ^((1)/(    6))`   = `(2^3)^((1)/(6))`

  =     `2^((3 xx 1/6))`   = `2^(1/2)`        = `sqrt(2)`



Question 260.

The value of `(256)^((5)/(4))` is


  1.    512
  2.    984
  3.    1024
  4.    1032
 Discuss Question
Answer: Option C. -> 1024

`(256)^((5)/(4))` =  `(4^4)^((5)/(4))` =   `4^((4 xx 5/4))` =  `4^5` =  1024.



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