Quantitative Aptitude

Number Series

2,662 Questions
All First differences and arithmetic progressions 812 Successive multiplication or division 429 Step-wise calculations 349 Squares and cubes based 338 Separate alternate positions 241 Inter-term operations 144 Mixed-operation rules 138 Unconventional pattern solving 74 Fractional and decimal operations 60 Prime number based 54 Digit operations 23

Number Series Questions

Multiple choice

Directions: In the following question, the numbers/letters are arranged in a sequence based on a certain principle. Select the answer from the four alternatives given under the sequence for the term marked by '?'. 19, 24, 31, 42, 55, 72, ?

  1. 83

  2. 89

  3. 91

  4. 93
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The differences between consecutive terms are: 24-19=5, 31-24=7, 42-31=11, 55-42=13, 72-55=17. These are consecutive prime numbers. The next prime after 17 is 19. So, 72 + 19 = 91.

Multiple choice

Number of identical terms in the sequences 2,5,8,11,…. upto 100 terms and 3,5,7,9,11,… upto 100 terms are

  1. 17

  2. 33

  3. 50

  4. 147
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sequence 1: 2, 5, 8, 11... (a=2, d=3). Sequence 2: 3, 5, 7, 9, 11... (a=3, d=2). Common terms are 5, 11, 17... (a=5, d=6). The general term is 5 + (n-1)6 = 6n - 1. We need 6n - 1 <= 299 (the 100th term of seq 1 is 2 + 99*3 = 299). 6n <= 300, so n <= 50. However, the 100th term of seq 2 is 3 + 99*2 = 201. So 6n - 1 <= 201, 6n <= 202, n <= 33.66. There are 33 terms.