Quiz Discussion

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 3rd and 9th term of an arithmetic progression are -8 and 10 respectively. What is the 16th term?

• 1] 34
• 2] 28
• 3] 25
• 4] 31

Find the 15th term of the sequence 20, 15, 10 . . . . .

• 1] -45
• 2] -55
• 3] -50
• 4] 0

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 the first 13 terms of an arithmetic progression if the first term is -10 and last term is 26?

• 1] 104
• 2] 140
• 3] 84
• 4] 98

If the sums of n terms of two arithmetic progressions are in the ratio \(\frac{{3n + 5}}{{5n + 7}}\)   then their nth terms are in the ration

• 1]

  \(\frac{{3n - 1}}{{5n - 1}}\)

• 2]

  \(\frac{{3n + 1}}{{5n + 1}}\)

• 3]

  \(\frac{{5n + 1}}{{3n + 1}}\)

• 4]

  \(\frac{{5n - 1}}{{3n - 1}}\)

The two geometric means between the number 1 and 64 are

• 1]

  8 and 16

• 2]

  2 and 16

• 3]

  4 and 8

• 4]

  4 and 16

The first term of an Arithmetic Progression is 22 and the last term is -11. If the sum is 66, the number of terms in the sequence are:

• 1] 10
• 2] 12
• 3] 9
• 4] 8

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 2^nd and 6^th term of an arithmetic progression are 8 and 20 respectively. What is the 20^th term?

• 1]

  56

• 2]

  62

• 3]

  65

• 4]

  69