Series pattern
The elements of the given series are the numbers formed by joining together consecutive add numbers in order
i.e, 1 and 3, 3 and 5, 5 and 7, 7 and 9, 9 and 11,...

Correct Option: A

Series pattern
The elements of the given series are the numbers formed by joining together consecutive add numbers in order
i.e, 1 and 3, 3 and 5, 5 and 7, 7 and 9, 9 and 11,...
∴ Missing tern = Number formed by joining 11 and 13 = 1113

Series pattern
62 + 5² = 62 + 25 = 87
87 + 10² = 87 + 100 = 187
187 + 15² = 187 + 225 = 412
412 + 20² = 412 + 400 = 812

Correct Option: B

Series pattern
62 + 5² = 62 + 25 = 87
87 + 10² = 87 + 100 = 187
187 + 15² = 187 + 225 = 412
412 + 20² = 412 + 400 = 812
812 + 25² = 812 + 625 = 1437
Should come in place of '?'

Series pattern
20 + 1² = 21,
21 + 2² = 25,
25 + 3² = 34,
34 + 4² = 50,

Correct Option: D

Series pattern
20 + 1² = 21,
21 + 2² = 25,
25 + 3² = 34,
34 + 4² = 50,
50 + 5² = 75 Should come in place of ' ? '
75 + 6² = 111

Let the first term and common term of the AP be a and d respectively.
Then, According to question ,
Sum of 6th and 15th elements = Sum of 7th, 10th and 12th elements
(a + 5d) + (a + 14d) = (a + 6d) + (a + 9d) + (a + 11d)
⇒ 2a + 19d = 3a + 26 d

Correct Option: B

Let the first term and common term of the AP be a and d respectively.
Then, According to question ,
Sum of 6th and 15th elements = Sum of 7th, 10th and 12th elements
(a + 5d) + (a + 14d) = (a + 6d) + (a + 9d) + (a + 11d)
⇒ 2a + 19d = 3a + 26 d
⇒ a + 7d = 0
∴ 8th term is 0.

Series pattern
16 + 1² = 17
Should come in place of 19

Correct Option: A

Series pattern
16 + 1² = 17
Should come in place of 19
17 + 2² = 21 ; 21+ 3² = 30;
30 + 4² = 46 ; 46 + 5² = 71
71 + 6² = 107
Clearly, 19 is wrong and will be replaced by 17.