Which of the following is not one of the main five types of reactions?

If you mean chemical reactions, the five types are Single replacement, Double replacement, Synthesis, Decomposition, and Combustion.
Are those the 5 to which you are referring?

6.
All of the numbers in every row and column add up to 15! (Also, 6 is the only number not represented out of numbers 1 through 9.)
And to the representation to his problem you can clear,y see that 4.6 seconds is actully the the time of the whole parking. so if you just do a simple equation... 4.6x10p/2x15/10x2 would get your answer to 6