Practice Test: Number Series- 2 - CAT MCQ

The series is 14, 28, 20, 40, 32, 64
Take three terms at a time. The notation be as follows:-
Let, First term = a = 14
It is evident that Second term= 2*a = 2 * 14 = 28 and,
The Third term = Second term - 8 OR ( 2*a - 8 ) = 28 - 8 = 20
Now consider the third, fourth and the fifth term.
Let, Third term = a = 20
It is evident that Fourth term= 2*a = 2 * 20 = 40 and,
The Fifth term = Second term - 8 OR ( 2*a - 8 ) = 40 - 8 = 32
Similarly consider fifth, sixth and the seventh(term to be found).
Let, Fifth term = a = 32
It is evident that Sixth term = 2*a = 2 * 32 = 64 and,
The Seventh term ( term to calculated) = Second term - 8 OR ( 2*a - 8 ) = 64 - 8 = 56
 

This is an alternating addition and subtraction series. In the first pattern, 10 is subtracted from each number to arrive at the next. In the second, 5 is added to each number to arrive at the next.

2*3 = 6
6*3 = 18
18*3 = 54
54*3 = 162

8 x 1 - 2 = 6
6 x 2 - 3 = 9
9 x 3 - 4 = 23
23 x 4 - 5 = 87
87 x 5 - 6 = 429

The pattern is 
4*2+1=9 
9*2+1=19 
19*2+1=39 
39*2+1=79 
79*2+1=159 
 

The letters decrease by 1; the numbers are multiplied by 2.

This is an alternating division and addition series: First, divide by 2, and then add 8.

This is a simple addition series; each number is 3 more than the previous number.

In this series, 5 is added to the previous number; the number 70 is inserted as every third number.

This is a simple alternating addition and subtraction series. The first series begins with 8 and adds 3; the second begins with 43 and subtracts 2.