Quiz Discussion

How many terms are there in the GP 5, 20, 80, 320........... 20480?

• 1] 5
• 2] 6
• 3] 8
• 4] 9
• 5] 7

The first and last term of an A.P. is a and l respectively. If S is the sum of all the terms of the A.P. and the common difference is given by $\frac{{{l^2} - {a^2}}}{{k - \left( {l + a} \right)}}$   then k = ?

• 1] S
• 2] 2S
• 3] 3S
• 4] None of these

Consider an infinite G.P. with first term a and common ratio r, its sum is 4 and the second term is 3/4, then

• 1]

  a = 7/4, r = 3/7

• 2]

  a = 2, r = 3/8

• 3]

  a = 3, r = 1/4

• 4]

  a = 3/2, r = ½

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

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