If a, b, c be in arithmetic progression, then the value of (a+2 b - c) (2 b + c - a) (a + 2 b + c) is
16 a b c
4 a b c
8 a b c
3 a bc
If 2/3, k, 5/8 are in AP, then value of k is
15
21
12
31/48
If twice the 11th terms of an AP is equal to 7 times its 21st term, then its 25th term is equal to.
24
120
0
None of these
Fifth term of a GP is 2, then the product of its 9 terms is
256
512
1024
1100
The 5th term of the series is
1/3
1
2/5
is equal to
n
1/n
1/2 (n+n-1)
1/2 (en + e-n)
The sum of the integers from 1 to 100 which are divisible by 3 and 5 is
2317
2632
315
2489
If three numbers a,b,c are in harmonic progression, then which of the following is true?
1/a, b, 1/c are in AP
1/bc, 1/ca, 1/ab are in HP
ab, bc, ca are in HP
a/b, b/c, c/a are in HP
The arithmetic means of first n odd natural number is
n2
2 n
3 n
If x = 1 + 2 + 4/2! + 8/3! + 16/4! + ...., then x-1 is equal to
e-2
e2
e1/2
