Tricks on how to solve series problems in reasoning quickly

Series questions are asked in almost all the competitive examination
in reasoning section. So it is very important for a candidate who is preparing
for competitive exams to solve series problems as quickly as possible and also
as accurately as possible. So here are some of the tricks that will give you
some idea on how to solve series questions in reasoning quickly.

To solve series questions in reasoning, you have to follow
the below given steps in order to solve the given series in shortest possible
time.

Step 1: check the series to see whether it is decreasing or
increasing or alternating.

Step 2: do this step if the series is increasing or
decreasing.

Check to see if the series in increasing gradually or
slowly. If it is so, then it might be an addition series. However if the series
is rising sharply but slows down later, then there is more chances that the
series might be formed by squared or cubed numbers. But if the series is equally
sharp throughout, then there are more chances that the series is multiplication
based (with or without addition or subtraction). The same idea also applies
when the series is decreasing (vice-versa).

If the rise of the series is irregular, then there might be
a mix of two series going alternately.

Now let us apply the above ideas to solve some example questions of series.

Find the next number in the series?

16, 17, 21, 30, 46, ?

You can see that the series is increasing first by 1, then
by 4, then by 9, then by 16. So the series is rising sharply. It means it
should be a series of squared or cubed numbers added at each step. Also when
you look at the difference of numbers (1,4,9,16, ?), you can easily figure out
that the difference of numbers are the squares of normal number series i.e.
1,2,3,4,?. So according to number series, 5 should come after 4. When we square
5, it equals 25. So we add 25 to 46 which equals 71. So 71 should be the next
number in the series.

Now let us take another example of a series.

Find next number in

-2, 4, 22, 58, 118, ?

Solution: as you can see the series increases sharply in the
start when it goes from 4 to 22, but then it slows down in the last. So it is
more likely to be a series in which addition of squared or cubed numbers is
done. Also there is a minus number in the series (-2), so it means there might
be something deducted from the series.

Upon checking the speedy rise, we can figure out that the
series increases by the below given pattern.

(1^3)-3= -2

(2^3)-4= 4

(3^3)-5= 22

(4^3)-6= 58

(5^3)-7= 118

(6^3)-8= 208

So 208 should be the next number in the series.

NOTE: it is very important to practice series question as
much as you can and as quickly as you can.

I hope, the above given tips will let you solve series
questions quickly.

Thanks

ANIL KUMAR