Insert one arithmetic mean between 3 and 13.

The angles of a polygon are in A.P. with common difference 5°. If the smallest angle is 120°, find the number of sides of the polygon.

If A, B and C are three arithmetic progressions (APs) as given below :

A = 2, 4, 6, 8, …….. upto n terms

B = 3, 6, 9, 12, …… upto n terms

C = 0, 4, 8, 12, …… upto n terms, then

out of A + B, A - C, C - B and B - A which is/are A.P. ?

1. A + B

2. A - C

3. C - B

4. All are A.P.

2k - 7, k + 5 and 3k + 2 are in A.P.; the value of k is :

1. -9

2. 6

3. -7

4. 5