Number Series Questions

The given series follows a pattern of +19, x19, +17, x17, +15, x15,...

Here the number which is to be replaced in ? is

41310+15=41325.

The given number series is 9 7 10 6 11 ?

Here in this we have two number sequences, they are

9, 10, 11, ... and 7, 6, 5, ...

Hence, the next number in the given number series is 6 - 1 = 5.

The given number series is 18, 90, 450, 2250, ?

18

18 x 5 = 90

90 x 5 = 450

450 x 5 = 2250

2250 x 5 = 11250

Hence, the next number in the given series is 11250.

The given sequence is a combination of three series:
i)1st, 4th, 7th terms i.e, 2, 4, 9
ii)2nd, 5th, 8th terms i.e, 3, 6, 12
iii)3rd, 6th, 9th terms i.e, 4, 8, 16
In each one of i, ii, iii, each term is twice the preceding term.
So, 9 is wrong and must be replaced by (4*2) = 8