GATE Questions

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The given number series is  21 56 102 160 231 316

21      56       102        160      231       316         416

   +35    +46       +58       +71      +85       +100

        +11      +12       +13      +14      +15

Hence, the next number in the given number series is 316 + 100 = 416.

Two series alternate here, with every third number following a different pattern.
In the main series, 4 is added to each number to arrive the next.
In alternate series, 5 is subtracted from each number t arrive the next number.
Here in the main series
3 + 4 = 7
7 + 4 = 11
11 + 4 = 15
15 + 4 = 19

In alternate series
24 - 5 = 19
19 - 5 = 14...

This is an alternating series in alphabetical order. The middle letters follow the order ABCDE. The first and third letters are alphabetical beginning with J. The third letter is repeated as a first letter in each subsequent three-letter segment.

Let the speed of the boat = p kmph

Let the speed of the river flow = q kmph

From the given data,

2 x 28p + q = 28p - q

=> 56p - 56q -28p - 28q = 0

=> 28p = 84q

=> p = 3q.

Now, given that if

$$\begin{gathered} 283q + 2q + 283q - 2q = 67260 \\ => 285q + 28q = 67260 \\ => q = 3 kmph \\ => x =3q = 9 kmph \end{gathered}$$

Hence, the speed of the boat = p kmph = 9 kmph and the speed of the river flow = q kmph = 3 kmph.

5 C in an OF denotes 5 Circles in an Olympic Flag.

These are riddles of type

12 S of the Z

52 W in a Y.

Let the cost price of a ball is Rs.x
Given, on selling 17 balls at Rs. 720, there is a loss equal to the cost price of 5 balls
The equation is :
17x - 720 = 5x
Solving the equation
we get x = 60
Therefore, cost price of a ball is Rs. 60.

Let the article costs 'X' to A
Cost price of B = 1.2X
Cost price of C = 0.75(1.2X) = 0.9X
Cost price of D = 1.4(0.9X) = 1.26X = 252
Amount paid by A for the article = Rs. 200.

The given series is 1/2, 1, 3/2, 6, 5/2, 3

1/2

1/2 + 1/2 = 1

1 + 1/2 = 3/2

3/2 + 1/2 = 2 (Not 6)

2 + 1/2 = 5/2

5/2 + 1/2 = 3

Hence, the odd man in the given number series is 6.