What is the length of the S-P interval, in seconds?

1. and 2. question: in which equation? or i don't understand you, 3. a), 4. c), 5. c), 6. b), 7. d), 8. d) if small number is underlined(behind symbol) , b) if big number is underlined(in front of symbol)9. what is underlined there? 10. c)

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab. 

Oxygen= 88ghydrogen= 12g