In a class of 30 IB students, 20 study mathematics SL, 12 study physics and 8 study both of these subjects. PLS HELP Find the probability that a randomly selected student does not study both of these subjects.

A. 11/15
B. 4/5
C. 4/15
D. 1/5

The first week samantha learned to read braille, she could read 10 words per minute. in the second week she increased her speed by 20%. in the third week she increased her speed again by another 25%. how many words could she read per minute by the third week? hurry and tell me!