Quiz Discussion

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

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

• 1] -45
• 2] -55
• 3] -50
• 4] 0

If the sum of three consecutive terms of an increasing A.P. is 51 and the product of the first and third of these terms is 273, then the third term is :

• 1] 13
• 2] 9
• 3] 21
• 4] 17

Find the n^th term of the following sequence :
5 + 55 + 555 + . . . . T_n

• 1]

   

  5(10ⁿ - 1) 

• 2]

   

  5ⁿ(10ⁿ - 1)

• 3]

  5/9×(10ⁿ−1)

     

• 4]

  (5/9)ⁿ×(10ⁿ−1)

If 7 times the seventh term of an Arithmetic Progression (AP) is equal to 11 times its eleventh term, then the 18th term of the AP will be

• 1] 0
• 2] 1
• 3] 2
• 4] -1

A piece of equipment cost a certain factory 6,00,000. If it depreciates in value, 15% the first year, 13.5% the next year, 12% the third year, and so on, what will be its value at the end of 10 years, all percentages applying to the original cost?

• 1] Rs. 2,00,000
• 2] Rs. 1,05,000
• 3] Rs. 4,05,000
• 4] Rs. 6,50,000

(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

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 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

If the sum of n terms of an A.P. is 3n2 + 5n then which of its terms is 164 ?

• 1] 26th
• 2] 27th
• 3] 28th
• 4] None of these