None of the above is the correct choice
Answer:The Answer is C,D and E
Step-by-step explanation:I just answered it on khan academy
The answer is B:40 hours. You take 200 divided by 20 to get 10 (the amount of 20 page sections he needs to read) and then multiply 10 by 4 (the speed he reads).
we are given
62% of the students take math
so,

49% take science

38% take both science and math
n(M∩S)=38
now, we can use union formula
n(M∪S)=n(M)+n(S) -n(M∩S)
now, we can plug values
and we get
n(M∪S)=62+49 -38
n(M∪S)=73
so,
the percentage takes at least one science or math course is 73%..........Answer
5.4x10^11 metres per second or 540,000,000,000 metres per second