Olympiad Test: Number Ranking - 1 - Class 8 MCQ

In the series
2 5 3 4 8 7 4 2 6 7 1 5 8 3 7 4 5 3
How many pair of successive numbers have a difference of 3?

How many 5’s are there in the sequence which are immediately preceded by 4 and immediately followed by 7?
2 3 4 5 6 1 4 5 7 1 2 4 5 7 3 8 4 5 9 6 5 3

How many pair of successive numbers are in the given series whose sum is 12?
4 5 7 3 2 8 4 9 1 5 6 4 8 3 1 9 3 5 7

How many pair of successive numbers are in the given series whose product is an even number?
6 1 4 6 3 5 1 7 2 6 3 5 7 1 8 3 7 5

How many 8’s are there in the series which are preceded by 5 but not followed by 7?
4 3 8 6 5 8 2 3 5 8 4 7 5 8 7 4

How many 9’s are there in the series which are preceded by 7 but not followed by 8?
4 2 9 6 7 9 2 4 7 9 8 4 7 9 3 6 8 9 

What is the product of sum of even digits and sum of odd digits in the number 8 6 7 4 3 5 2?