Quiz Discussion

The common difference of the A.P. \(\frac{1}{3}, \frac{{1 - 3b}}{3} , \frac{{1 - 6b}}{3}\)   . . . . . . is

• 1]

  \(\frac{1}{3}\)

• 2]

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

• 3]

  -b

• 4]

  b

If four numbers in A.P. are such that their sum is 50 and the greatest number is 4 times the least, then the numbers are

• 1] 5, 10, 15, 20
• 2] 4, 10, 16, 22
• 3] 3, 7, 11, 15
• 4] None of these

How many 2-digit positive integers are divisible by 4 or 9?

• 1]

  32

• 2]

  22

• 3]

  34

• 4]

  30

In an A.P., if d = -4, n = 7, a_n = 4, then a is

• 1]

  6

• 2]

  7

• 3]

  20

• 4]

  28

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

• 1] 5
• 2] 6
• 3] 8
• 4] 9
• 5] 7

(1) + (1 + 1) + (1 + 1 + 1) + ....... + (1 + 1 + 1 + ...... n - 1 times) = ......

• 1]

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

• 2]

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

• 3]

  \({n^2}\)

• 4]

  n

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 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 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]

  9

• 2]

  10

• 3]

  11

• 4]

  12

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