GATE Questions

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The given number series 999, 990, 998, 991, 997, 992, ?

It follows a pattern that,

999

999 - 9 = 990

990 + 8 = 998

998 - 7 = 991

991 + 6 = 997

997 - 5 = 992

992 + 4 = 996

Hence, the next number in the given number series is 996.

The given series follows a pattern of +19, x19, +17, x17, +15, x15,...

Here the number which is to be replaced in ? is

41310+15=41325.

Since each ring consists of six different letters, the total number of attempts possible with the three rings is = 6 x 6 x 6 = 216. Of these attempts, one of them is a successful attempt.

Maximum number of unsuccessful attempts = 216 - 1 = 215.

Only one such symbol is there in the given arrangement.

It is 4@5.

From the given data,

Let the two gits of a number be x & y

A) x + y = 15

B) x2 - y2 = 45

(x+y) (x - y) = 45

C) x - y = 3

From any 2 of the given 3 statements, we can find that 2 digit number as 

2x = 18 => x = 9

=> y = 6

Hence, 2 digit number is 96.

Any one pair of A and B, B and C or C and A is sufficient to find.

Let Rajeev's present age be  x years.

Rajeev's age after 15 years = (x + 15) years.

Rajeev's age 5 years back = (x - 5) years

Then ATQ, 

x + 15 = 5 (x - 5)

x + 15 = 5x - 25

=> x = 10

Hence, Rajeev's present age = x = 10 years.