GATE CS 2018

Question 1

What is the missing number in the following sequence? 2, 12, 60, 240, 720, 1440, .... 0

• A. 2880
• B. 1440
• C. 720
• D. 0

Answer: (B)

GATE CS 2018 Arithmetic Aptitude Numbers Series
Discuss it

The series starts with 2. We multiply first term with 6 to get second term 12 Then we multiply second term with 5 to get third term 60 Then we multiply third term with 4 to get fourth term 340 Then we multiply fourth term with 3 to get fifth term 720 Then we multiply fifth term with 2 to get fifth term 1440. Then we need to multiply with 1 and we get 1440 again.

Question 2

What would be the smallest natural number which when divided either by 20 or by 42 or by 76 leaves a remainder ‘7’ in each case is_

• A. 3047
• B. 6047
• C. 7987
• D. 63847

Answer: (C)

GATE CS 2018 General Aptitude Arithmetic Aptitude LCM
Discuss it

We need a number that can be written as 20x + 7, 42y + 7, 76z + 7 for three integers x, y and z. We basically need to find least common multiple of 20 (2 * 2 *5), 42(2 * 3 * 7) and 76(2 * 2 * 19) which is 2 * 2 * 5 * 3 * 7 * 19 = 20 * 21 * 19 = 420 * 19 = 7980 So our number is 7980 + 7 = 7987. Note - You can also verify options using virtual calculator.

Question 3

"From where are they bringing their books? _________ bringing _________ books from _________." The words that best fill the blanks in the above sentence are

• A. Their, they're, there
• B. They're, their, there
• C. There, their, they're
• D. They're, there,there

Answer: (B)

GATE CS 2018 General Aptitude English
Discuss it

"From where are they bringing their books? Who bringing Whose books from Where." Who - A group as subject = They are Whose - of that group = their Where - from a place = there "From where are they bringing their books? They are bringing their books from there." So, option (B) is correct choice.

Question 4

A __________ investigation can sometimes yield new facts, but typically organized once are more successful.

• A. Meandering
• B. Timely
• C. Consistent
• D. Systematic

Answer: (A)

GATE CS 2018 General Aptitude English
Discuss it

Meandering (as adjective) = proceeding in a convoluted or undirected fashion. Timely (as adjective) = done or occurring at a favourable or useful time; opportune. Consistent (as adjective) = acting or done in the same way over time, especially so as to be fair or accurate. Systematic (as adjective) = done or acting according to a fixed plan or system; methodical. Therefore, meandering is correct choice, all other options are similar to the word organized.

Question 5

What is the area of the circle which has the diagonal of the square as its diameter if the area of square is ' d ' ?

• A. πd
• B. πd²
• C. (1/4) πd²
• D. (1/2)πd

Answer: (D)

GATE CS 2018 General Aptitude Trigonometry & Height and Distances
Discuss it

One important observation to solve 
the question :

Diagonal of Square = Diameter of Circle.

Let side of square be x. 

From Pythagoras theorem.
Diagonal = √(2*x*x)

We know area of square = x * x = d

Diameter = Diagonal =  √(2*d)

Radius = √(d/2)
Area of Circle = π * √(d/2) * √(d/2) = 1/2 * π * d

Question 6

In the figure below, ∠DEC+∠BFC is equal to _______ .

• A. ∠ BCD - ∠ BAD
• B. ∠ BAD + ∠ BCF
• C. ∠ BAD + ∠ BCD
• D. ∠ CBA + ∠ ADC

Answer: (A)

GATE CS 2018 General Aptitude Mensuration 2D
Discuss it

Option (A) is correct.

Question 7

In a party, 60% of the invited guests are male and 40% are female. If 80% of the invited guests attended the party and if all the invited female guests attended, what would be the ratio of males to females among the attendees in the party?

• A. 2:3
• B. 1:1
• C. 3:2
• D. 2:1

Answer: (B)

GATE CS 2018 General Aptitude Set Theory & Algebra Ratio and Proportion 50 Aptitude & Reasoning MCQs with Answers
Discuss it

Let total males and females be 60x and
40x respectively.

Total number of people = (60x + 40x)
Total number of people who attended : 
                 0.8(60x + 40x) = 80x

Let y males attended. It is given all 
1females attended 

40x + y = 80x
y = 40x which is same as females.

Alternative Approach - Lets total number of people = 100. Therefore, 60 are male and and 40 are female. But total 80 guests are attended and all 40 female attended the party. So, there remaining (80 - 40 = 40) attendees should be male. Then the ration of male to female among attendees is 40 : 40 = 1 : 1

Question 8

A six sided unbiased die with four green faces and two red faces is rolled seven times. Which of the following combinations is the most likely outcome of the experiment?

• A. Three green faces and four red faces.
• B. Four green faces and three red faces.
• C. Five green faces and two red faces.
• D. Six green faces and one red face

Answer: (C)

GATE CS 2018 General Aptitude Arithmetic Aptitude Probability 50 Aptitude & Reasoning MCQs with Answers
Discuss it

Considering uniformly distributed outcomes, we get 4 greens and 2 reds in six throws. Then in one more throw, green is more likely. So, option (C) is correct.

Question 9

If pqr ≠ 0 and p^(-x) = 1/q, q^(-y) = 1/r, r^(-z) = 1/p, find the value of the product xyz ?

• A. -1
• B. 1 / pqr
• C. 1
• D. pqr

Answer: (C)

GATE CS 2018 General Aptitude Arithmetic Aptitude Algebra 50 Aptitude & Reasoning MCQs with Answers
Discuss it

Taking logs of given three values, we get

1/q = p-x -------(1)
1/r = q-y -------(2)
1/p = r-z -------(3)

1/q = p-x
    = r-xz [Putting value of p from (3)]
    = q-xyz  [Putting value of r from (2)]
    = 1 / qxyz

On comparing power of q both sides, we get xyz = 1

So, option (C) is correct.

Question 10

In appreciative of social improvement completed in a town, a wealthy philanthropist decided to give gift of Rs. 750 to each male senior citizen and Rs. 1000 for female senior citizens. There are total 300 senior citizens and th 8/9^th of total men and 2/3^rd of total women claimed the gift. What is amount of money philanthropist paid?

• A. 15000
• B. 200000
• C. 115000
• D. 151000

Answer: (B)

GATE CS 2018 General Aptitude Arithmetic Aptitude Ratio and Proportion
Discuss it

Let there be x total men.

Total amount paid = x * 750 * 8/9 + (300 - x)*1000*2/3
                  = x*2000/3 + 300*1000*2/3 - x*2000/3
                  = 200000