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us1903 • Jan 13, 2009

Find the missing number..

3, 5, 7, 11, 13, 17, ___

a)19
b)21
c)23
d)25

How can I start with such problems? Please give me a general idea to solve such questions.
raj87verma88 • Jan 13, 2009
the next no. is 19 and then 23. The sequence consists of prime numbers.
Kaustubh Katdare • Jan 13, 2009
us1903
3, 5, 7, 11, 13, 17, ___

a)19
b)21
c)23
d)25

How can I start with such problems? Please give me a general idea to solve such questions.
To tell you the truth, the only way to get better at cracking such problems is to solve as many problems as you can and paying attention to the way it has been cracked.

Also, try to form your own questions from existing questions and solve them. For example, can you give me a number before the first number in the series (3)?

😀

Options -

1)1
2)2
3)N/A
4)0
shalini_goel14 • Jan 14, 2009
Is the answer is 19? For Big_K's question, answer is 2? Am I right?
Kaustubh Katdare • Jan 14, 2009
2 is the only even prime 😀
shalini_goel14 • Jan 15, 2009
The_Big_K
2 is the only even prime 😀
Doesn't matter , it is prime .😉
cool...the answer by The BIG K is correct but if none minds i have a small correction in that one.
For solving these kind of problems we need to have a thorough knowledge of what are actually numbers.
they are not only 0-9 but they have many types and characteristics.
i can suggest a book QA for CAT by Arun Sharma.
if you know the characteristics of numbers you can easily find the solutions , and as BIG K said after getting the basics solve books like Puzzles from Shakunthala Devi. i am sure in about 1 month you will be able to answer all the queastions of that sort.
mata • Feb 6, 2009
us1903
3, 5, 7, 11, 13, 17, ___

a)19
b)21
c)23
d)25

How can I start with such problems? Please give me a general idea to solve such questions.
hey it's very simple............ans is 19 . just check all are prime no.s.

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