Quiz Discussion

If the nth term of an A.P. is 2n + 1, then the sum of first n terms of the A.P. is

• 1] n(n - 2)
• 2] n(n + 2)
• 3] n(n + 1)
• 4] n(n - 1)

For A.P. T18 - T8 = ........ ?

• 1] d
• 2] 10d
• 3] 26d
• 4] 2d

If the sum of p terms of an A.P. is q and the sum of q terms is p, then the sum of (p + q) terms will be

• 1] 0
• 2] p - q
• 3] p + q
• 4] -(p + q)

If the fifth term of a GP is 81 and first term is 16, what will be the 4th term of the GP?

• 1] 36
• 2] 18
• 3] 54
• 4] 24
• 5] 27

If a + 1, 2a + 1, 4a - 1 are in A.P., then the value of a is:

• 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

Which term of the A.P. 92, 88, 84, 80, ...... is 0?

• 1] 23
• 2] 32
• 3] 22
• 4] 24

The sum of the first four terms of an A.P. is 56. The sum of the last four terms is 112. If its first term is 11, the number of terms is

• 1]

  10

• 2]

  11

• 3]

  12

• 4]

  13

The sum of n terms of an A.P. is 3n2 + 5n, then 164 is its

• 1] 24th term
• 2] 27th term
• 3] 26th term
• 4] 25th term

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