1
NDA Mathematics 4 September 2022
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language

Consider the following statements :

1. 2 + 4 + 6 + ........ + 2n = n2 + n

2. The expression n2 + n + 41 always gives a prime number for every natural number n

Which of the above statements is/are correct ?

A
1 only
B
2 only
C
Both 1 and 2
D
Neither 1 nor 2
2
NDA Mathematics 4 September 2022
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language

Let P be the sum of first n positive terms of an increasing arithmetic progression A. Let Q be the sum of first n positive terms of another increasing arithmetic progression B.

Let P ∶ Q = (5n + 4) ∶ (9n + 6)

What is the ratio of the first term of A to that of B ?
A
1/3
B
2/5
C
3/4
D
3/5
3
NDA Mathematics 4 September 2022
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language

Let P be the sum of first n positive terms of an increasing arithmetic progression A. Let Q be the sum of first n positive terms of another increasing arithmetic progression B.

Let P ∶ Q = (5n + 4) ∶ (9n + 6)

What is the ratio of their 10th terms ?
A
11/29
B
22/49
C
33/59
D
44/69
4
NDA Mathematics 4 September 2022
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language

Let P be the sum of first n positive terms of an increasing arithmetic progression A. Let Q be the sum of first n positive terms of another increasing arithmetic progression B.

Let P ∶ Q = (5n + 4) ∶ (9n + 6)

If d is the common difference of A, and D is the common difference of B, then which one of the following is always correct ?
A
D > d
B
D < d
C
7D > 12d
D
None of the above
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