Quiz Discussion

Let S denotes the sum of n terms of an A.P. whose first term is a. If the common difference d is given by d = S_n – k S_n-1 + S_n-2 then k =

• 1]

  1

• 2]

  2

• 3]

  3

• 4]

  4

Sum of n terms of the series \(\sqrt 2   +   \sqrt 8   +   \sqrt {18}   +   \sqrt {32}   +  \) ....... is

• 1]

  \(\frac{{n\left( {n + 1} \right)}}{2}\)

• 2]

  \(2n\left( {n + 1} \right)\)

• 3]

  \(\frac{{n\left( {n + 1} \right)}}{{\sqrt 2 }}\)

• 4]

  1

The 7th and 21st terms of an AP are 6 and -22 respectively. Find the 26th term

• 1] -34
• 2] -32
• 3] -12
• 4] -10
• 5] -16

What is the sum of all positive integers up to 1000, which are divisible by 5 and are not divisible by 2?

• 1] 10,050
• 2] 5050
• 3] 5000
• 4] 50,000

The 3rd and 7th term of an arithmetic progression are -9 and 11 respectively. What is the 15th term?

• 1] 28
• 2] 87
• 3] 51
• 4] 17

The sum of first five multiples of 3 is:

• 1]

  90

• 2]

  72

• 3]

  55

• 4]

  45

What is the sum of all 3 digit numbers that leave a remainder of '2' when divided by 3?

• 1]

  897

• 2]

  1,64,850

• 3]

  1,64,749

• 4]

  1,49,700

What is the sum of the first 12 terms of an arithmetic progression if the 3^rd term is -13 and the 6^th term is -4?

• 1]

  -30

• 2]

  41

• 3]

  -23

• 4]

  -34

If the 7^th term of a H.P. is 1/10 and the 12^th term is 1/25, then the 20^th term is

• 1]

  1/41

• 2]

  1/45

• 3]

  1/49

• 4]

  1/37

If a, b, c are in A.P., then (a – c)²/ (b² – ac) =

• 1]

  3

• 2]

  4

• 3]

  1

• 4]

  2