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

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

• 1] 23
• 2] 32
• 3] 22
• 4] 24

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

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

• 1] 6
• 2] 7
• 3] 20
• 4] 28

If a, b, c are in A.P., then (a – c)²/ (b² – ac) =

• 1]

  3

• 2]

  4

• 3]

  1

• 4]

  2

The 3^rd and 7^th term of an arithmetic progression are -9 and 11 respectively. What is the 15^th term?

• 1]

  28

• 2]

  87

• 3]

  51

• 4]

  17

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 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

Consider an infinite G.P. with first term a and common ratio r, its sum is 4 and the second term is 3/4, then

• 1]

  a = 7/4, r = 3/7

• 2]

  a = 2, r = 3/8

• 3]

  a = 3, r = 1/4

• 4]

  a = 3/2, r = ½

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)