How many even numbers are there in the following series of numbers, each of which is immediately preceded by an odd number, but not immediately followed by an even number? 5 3 4 8 9 7 1 6 5 3 2 9 8 7 3 5

3

According to the question, the condition which needs to be fulfilled is:

Odd number - Even numbers →Χ Even number

There are 3 pairs which fulfill the above condition. 

5 3 4 8 9 7 1 6 5 3 2 9 8 7 3 5

5 3 4 8 9 7 1 6 5 3 2 9 8 7 3 5