Quiz Discussion

If k, 2k – 1 and 2k + 1 are three consecutive terms of an AP, the value of k is

• 1] -2
• 2] 3
• 3] -3
• 4] 6

If the 3rd and the 5th term of an arithmetic progression are 13 and 21, what is the 13th term?

• 1] 53
• 2] 49
• 3] 57
• 4] 61

The 3rd and 6th term of an arithmetic progression are 13 and -5 respectively. What is the 11th term?

• 1] -29
• 2] -41
• 3] -47
• 4] -35

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

The number of terms of the A.P. 3, 7, 11, 15, ....... to be taken so that the sum is 406 is

• 1]

  5

• 2]

  10

• 3]

  12

• 4]

  14

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

If the sum of n terms of an A.P. be 3n2 + n and its common difference is 6, then its first term is

• 1] 2
• 2] 3
• 3] 1
• 4] 4

A bacteria gives birth to two new bacteria in each second and the life span of each bacteria is 5 seconds. The process of the reproduction is continuous until the death of the bacteria. initially there is one newly born bacteria at time t = 0, the find the total number of live bacteria just after 10 seconds :

• 1]

  \(\frac{{{3^{10}}}}{2}\)

• 2]

  310 - 210

• 3]

  243 × (35 -1)

• 4]

  310 - 25

• 5]

  None of these

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 nth term of an A.P., the sum of whose n terms is Sn, is

• 1] Sn + Sn - 1
• 2] Sn - Sn - 1
• 3] Sn + Sn + 1
• 4] Sn - Sn + 1