I originally put 10 seconds as the answer, but it says it is still wrong. Any help?

The answer is 30 but I don't know how it arrived at that answer! Please explain

2.

Tom Cogwagee Longboat, of the Six Nations of the Grand River, is one of Ontario's best known distance runners. In 1907, he set a new Boston Marathon record, beating all of the previous decade's champions by almost 5 minutes! If he ran the 39.2 km course in 2 hours, 24 minutes and 24 seconds, what was his speed? HINT: we'll need our units to be metres per second - what do you need to convert in the question? 0.221 m/s O 0.272 m/s O 4.52 m/s O 17.5 m/s

Suppose a machine is invented to measure the amount of knowledge in a student’s head in units called “factoids.” One student is measured at F(t) = t³ − 6t² + 9t factoids at time t, where t is measured in weeks. a. Find the rate at which the student is gaining (or losing) knowledge as a function of time (be sure to give the units). b. During what time between t = 0 and 11 is the student losing knowledge? c. Sketch a graph of the function F(t).

Jake’s height is measured to be 67 ???ℎ??; Enrique’s height is measured as 67.2 ???ℎ??. Can we use these two measurements to determine who is taller? Use your understanding of approximate numbers to explain why or why not.

Could anyone please let me know the reason for having b) an incorrect answer? In the correct unit. Please

The following times are given using metric prefixes on the base SI unit of time: the second. Rewrite them in scientific notation without the prefix (in s). For example, 47 Ts would be rewritten as 4.7 ✕ 1013 s. (Enter your answers as m ✕ 10n, where 1 ≤ |m| < 10  and n is an integer.) 984 Ps 986 fs 19 ns 572 µs

It's showing that b is not correct. Thank you for your help with this practice problem.

I am a little confused on this question , please help. Thank you for your time!   I have attached the problem .Please view attachment before answering. Thank you again!