GATE CS 2018

Last Updated : 22 Nov, 2021
Question 1
What is the missing number in the following sequence? 2, 12, 60, 240, 720, 1440, .... 0
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2880
Tick
1440
Cross
720
Cross
0


Question 1-Explanation: 
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_
Cross
3047
Cross
6047
Tick
7987
Cross
63847


Question 2-Explanation: 
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
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Their, they\'re, there
Tick
They\'re, their, there
Cross
There, their, they\'re
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They\'re, there,there


Question 3-Explanation: 
\"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.
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Meandering
Cross
Timely
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Consistent
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Systematic


Question 4-Explanation: 
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 ' ?

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πd

Cross

πd2

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(1/4) πd2

Tick

(1/2)πd



Question 5-Explanation: 

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 _______ . GATE-CS-2018-Question
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∠ BCD - ∠ BAD
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∠ BAD + ∠ BCF
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∠ BAD + ∠ BCD
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∠ CBA + ∠ ADC


Question 6-Explanation: 
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?
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2:3
Tick
1:1
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3:2
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2:1


Question 7-Explanation: 
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?
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Three green faces and four red faces.
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Four green faces and three red faces.
Tick
Five green faces and two red faces.
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Six green faces and one red face


Question 8-Explanation: 
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 ?

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-1

Cross

1 / pqr

Tick

1

Cross

pqr



Question 9-Explanation: 

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 citizens and the 8/9th of total men and 2/3rd of total women claimed the gift. What is amount of money philanthropist paid?

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15000

Tick

200000

Cross

115000

Cross

151000



Question 10-Explanation: 
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
There are 66 questions to complete.

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