Explanation

3 × 3 = 9 - 1 = 8

8 × 3 = 24 - 2 = 22

22 × 3 = 66 - 3 = 63

63 × 3 = 189 - 4 = 189

Explanation

13 × 2 = 26 - 2 = 24

24 × 2 = 48 - 2 = 46

46 × 2 = 92 - 2 = 90

90 × 2 = 180 - 2 = 178

Explanation

Let suppose original price = x

25% of x 25% X x

x- 25%x = 900

x - 25/100 x = 900

100x - 25x = 90000

75x = 90000

x=1200

Explanation

The given sequence is:

3, 4, 7, 8, 11, 12

Form differences between two consecutive numbers in the sequence as follows:

4 - 3 = 1

7 - 4 = 3

8 - 7 = 1

11 - 8 = 3

12 - 11 = 1

X- 12 = 3

= 15

Explanation

We see that 32 + 8 = 40 and 32 – 8 = 24. Now let us check this rule for one more term. We see that 16 + 8 = 24. Therefore this works for more than half of the given numbers. Hence the rule is correct. Therefore the missing number in the series is 16 – 8 =  8. The answer is  8.

Explanation

If each group comprises of 2 handshakes than total handshakes of all the individuals are 120*2 handshakes = 240

taking Lcm 240 = 16*15 hence 16 persons in total

Explanation

Suppose the value of the house is X then 

160 = 2_5 ×X

160 = 2_5 X 1_100 × X

160 × 500 2X

80000 = 2X

X = 40000

Explanation

The sequence consists of perfect squares

. The n-th term of the sequence is ((n+2)^2.

3*3  = 9

4*4  = 16

5*5  = 25

6*6  = 36

7*7  = 49

Explanation

=-2000÷10 : 250÷10

= 200÷5 : 25 ÷ 5

= 40÷5 : 5÷5

= 8:1

Explanation

1+2 = 3
3x2 = 6+2 =8
8x2 = 16+3 =19
19x2 = 38+4 = 42
42x2 = 84+5 = 89