7, 4, 5, 9, 20, 51, 106.5

Correct Answer: 621

Explanation:

As per above given series , we can see that
Descending order of given series -
Next term = ( 5 x previous term ) + odd number ( which starts 3 )
Here , 5th term = 4
4th term = 5 × 5th term + 3
? 4th term = 5 × 4 + 3 = 23
3rd term= 5 × 4th term + 7
? 3rd term= 5 × 23 + 7 = 122
Similarly , we can find all others terms also.
2nd term = 5 × 3rd term + 11
? 2nd term = 5 × 122 + 11 = ?
? ? = 621
1st term = 5 × 2nd term + 15
? 1st term = 5 × 621 + 15 =3120

Correct Answer: 16

Explanation:

The given series is in the below pattern,we can see that
Square root of ( First term - Third term ) = Second term
? Square root of ( 251 ? 107 ) = Square root of 144 = 12 = Second term
Square root of ( Fourth term - sixth term ) = Fifth term
? 381 ? 125 = Square root of 256 = 16 = Fifth term
? Fifth term ( ? ) = 16
Hence, 16 is the missing number in the given question.

Correct Answer: 120

Explanation:

As per given series , we can see that
First term = 1
Second term = First term × 2
? Second term = 1 × 2 = 2
Similarly we can find the all others terms
Third term = Second term × 3
? Third term = 2 × 3 = 6
Fourth term = Third term × 4
? Fourth term = 6 × 4 = 24
Fifth term = Fourth term × 5
? Fifth term = 24 × 5 = ?
? ? = 120
Sixth term = Fifth term × 6
? Sixth term = 120 × 6 = 720

Correct Answer: 3

Explanation:

The number pattern is described in the below image.
As per figure we can see the number series is in specific pattern which will help us to find the next number.
It is clear that we are getting the next terms on adding + 1 , + 3 , + 5 , + 7 , + 9 in previous term respectively.
First term = - 1
Second term = First term + 1
? Second term = -1 + 1 = 0
Third term = Second term + 3
? Third term = 0 + 3 = ( ? )
? ( ? ) = 3
Similarly we can calculate the all others terms
? Fourth term = 8
? Fifth term= 15

Correct Answer: 124

Explanation:

The given series is in the below pattern,we can see that
Next term ( T_n ) = n³ - 1 { where , putting n = 1 , 2 , 3 , 4 , 5 respectively }
First term = T₁ = 1³ - 1 = 0
Second term = T₂ = 2³ - 1 = 7
Similarly we can find the all others terms
Third term = 26
Fourth term = 63
Fifth term( ? )= 124
Hence we get the value of ? = 124

Correct Answer: 20

Explanation:

The series is 18 +1² = 19; 19 + 2² = 23; 23 + 3² = 32;
32 + 4² = 48; 48 + 5² = 73 + 6² = 109

Correct Answer: 72

Explanation:

The series is x 2 + 1, x 2 + 2, x 2 + 3, x 2 + 4, x 2 + 5

Correct Answer: 138

Explanation:

(2 - 1) x 7 = 7; (7 - 2) x 6 = 30; (30 - 3) x 5 = 135; (135 - 4) x 4 = 524;
(524 - 5) x 3 = 1557; (1557 - 6) x 2 = 3102

Correct Answer: 14

Explanation:

The series is x 2 - 2, x 2 - 2, x 2 - 2, x 2 - 2, ......

Correct Answer: 356

Explanation:

Pattern is x 2 + 1, x 3 + 1, x 2 + 1, x 3 + 1, ........