# Cocubes Computer Fundamentals Questions And Answers

Cocubes Computer Fundamentals MCQs : This section focuses on "Computer Fundamentals" of Cocubes Exam. These Multiple Choice Questions (MCQ) should be practiced to prepare for Cocubes Exam, entrance exams and other competitive examinations.

1. A, B and C can all together do piece of work in 20 days, in which B takes twice as long as A and C together do the work and C takes twice as long as A and B together take to do the work. In how many days B can alone do the work?

A. 40

B. 35

C. 60

D. 45

View Answer

Ans : C

Explanation: (A+C) in x days so B completes in 2x days then (1/x) + (1/2x) = 1/20

solve, x = 30, so B 2x = 60days

2. The cost price of item B is Rs. 200/- more than the cost price of item A. Item A was sold at a profit of 20% and item B was sold at a loss of 30%. If the respective ratio of selling prices of items A and B is 6 :7, what is the cost price of item B?

A. Rs. 520

B. Rs. 400

C. Rs. 430

D. Rs. 360

View Answer

Ans : B

Explanation: Let the CP of item A be x, CP of item B is x+200.

(120/100*x)/(x+200)*70/100 = 6/7

120x/(x+200)*70=6/7

20x/10(x+200) = 1

X=Rs. 200. CP of item B is 200+200 = Rs. 400.

3. If A =x% of y and B =y%of x, then which of the following is true?

A. A is equal to B

B. A is smaller than B

C. A relationship between A and B cannot be determined

D. If x is greater than y, then A is less than B

View Answer

Ans : A

Explanation: A=(x/100)*y=xy/100

B=(y/100)*x=xy/100

Therefore A=B

4. What is the largest 3 digit number exactly divisible by 18?

A. 978

B. 954

C. 980

D. 990

View Answer

Ans : D

Explanation: Largest 3 digit number = 999

999 ÷ 18 = 55, remainder = 9

Hence largest 3 digit number exactly divisible by 18

= 999 - 9 = 990

5. A vessel contains 180 litres of mixture of milk and water in the respective ratio of 13 : 5. Fifty-four litres of this mixture was taken out and replaced with 6 litres of water, what is the approximate percentage of water in the resultant mixture?

A. 41

B. 31

C. 24

D. 9

View Answer

Ans : B

Explanation: Milk: water = 13:5

Volume of solution=180

Solution taken out= 54

Volume of solution left= 180-54=126

In 126 l solution,

Milk= 126*13/18= 91

Water=126*5/18=35

As 6 l water is added

Water= 35+6= 41

Total solution volume= 126+6= 132

Percentage of water= 41/132*100= 31%

6. The HCF and LCM of two num¬bers are 12 and 924 respectively. Then the number of such pairs is

A. 0

B. 1

C. 2

D. 3

View Answer

Ans : A

Explanation: Let the numbers be 12x and 12y where x and y are prime to each other.

∴ LCM = 12xy

∴ 12xy = 924

⇒ xy = 77

∴ Possible pairs = (1, 77) and (7,11)

7. The ages of the two persons differ by 20 years. If 5 year ago, the older one be 5 times as old as the younger one, then their present ages, in year are:

A. 24, 4

B. 30, 10

C. 20, 10

D. 15, 45

View Answer

Ans : B

Explanation: Let the age be x and y years now.

Then, x−y=20 -------- (i)

and (x−5)=5(y−5) ------- (ii)

On solving both equation we get:

x=30 and y=10

8. What will be unit’s digit in the result of the expression

3^69 * 7^71 * 9^5?

A. 6

B. 4

C. 1

D. 7

View Answer

Ans : C

Explanation: Unit digit in 3^4 = 1

Unit digit in (3^4)^17 = 1

Unit digit in 3^(69)

= Unit digit in [ (3^4)^17 x 3 ] = (1 x 3) = 3

Unit digit in 7^4

= Unit digit in (7^4)^17 is 1.

Unit digit in 7^(71)

= Unit digit in [(7^4)^17 x 7^3] = (1 x 3) = 3

Unit digit in 9^5 = 9

Required digit = Unit digit in (3 x 3 x 8) = 1

9. The ratio of the volumes of two cubes is 729: 1331. What is the ratio of their total surface areas?

A. 81 : 121

B. 729 : 1331

C. 0.384027777777778

D. 27 : 121

View Answer

Ans : A

Explanation: Ratio of the sides = ³√729 : ³√1331 = 9 : 11

Ratio of surface areas = 9^2 : 11^2 = 81 : 121

10. Find the Value of tan60° + tan120°?

A. half

B. one

C. one-third

D. zero

View Answer

Ans : D

Explanation: tan(60) + tan(180-120)

=tan(60)+(-tan(60)) [because in second quadrant tan is -ve]

=0

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