Multiple or Add

smithy38

New member
Joined
Jul 9, 2016
Messages
9
Last year 453 new students took the English entrance test. 215 were placed in remedial English. 163 passed remedial English. If a student who took the test is selected randomly. Estimate the probability that:
a) The student who took the test took remedial English.
b) The student who took the test passed remedial English.
c) A student who took remedial English did not pass it.

the answer to a)

215/453= 0.4746the answer to b) is what I question;

163/453= 0.3598 is the number out of all that passed remedial English
So does the answer become (0.4746 + 0.3598) or is the answer (0.4746 x 0.3598)
 
Last year 453 new students took the English entrance test. 215 were placed in remedial English. 163 passed remedial English. If a student who took the test is selected randomly. Estimate the probability that:
a) The student who took the test took remedial English.
b) The student who took the test passed remedial English.
c) A student who took remedial English did not pass it.

the answer to a)

215/453= 0.4746the answer to b) is what I question;

163/453= 0.3598 is the number out of all that passed remedial English
So does the answer become (0.4746 + 0.3598) or is the answer (0.4746 x 0.3598)

Of the 453 we have 248 passing the test and NOT being placed in remedial english (assuming that ALL the students that flunked the test were placed in remedial class). These 258 students did not take "remedial English"

a) The student who took the test took remedial English. = 215/453 (assuming whoever was "placed" in the class, "took" the class - i.e. nobody said quit)
b) The student who took the test passed remedial English. = 163/453
c) A student who took remedial English did not pass it. = (215-163)/215
 
Of the 453 we have 248 passing the test and NOT being placed in remedial english (assuming that ALL the students that flunked the test were placed in remedial class). These 258 students did not take "remedial English"

a) The student who took the test took remedial English. = 215/453 (assuming whoever was "placed" in the class, "took" the class - i.e. nobody said quit)
b) The student who took the test passed remedial English. = 163/453
c) A student who took remedial English did not pass it. = (215-163)/215

Thanks for your response, 238 seemed to have passed and were not required to take remedial English.

I approached the b) question as either being 'independent' or as 'dependent' upon the whole sample, thus my confusion. I thought those that passed remedial English (163) were a subset of those that took remedial English so I was under the impression that this probability had to be adjusted for the result of a)
 
Top