Two hundred students have enrolled in at least one Grade 12 university course this year:
70 are in Chemistry
110 are in Physics
67 are in Biology
60 are in Chemistry and Physics
35 are in Physics and Biology
13 are in Biology and Chemistry
7 are in Chemistry, Biology and Physics
a) Determine the probability that a student selected at random from the group is taking Biology
b) Determine the probability that a student selected at random from the group is taking Chemistry or Physics
2007-06-26 04:17:39 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
a) This one is pretty straightforward. You have 67 taking biology and 200 students total, so the answer is just: 67/200
b) This one is a little bit harder. You have 70 in chemistry and 110 in physics, but that counts those who are in both classes twice. If you subtract the number in both classes (60), then you'll correct the double-counting of those students taking both classes, and you'll have left the number taking either one:
(70 + 110 - 60)/200 = 120/200 = 3/5
2007-06-26 04:20:41 · answer #1 · answered by McFate 7 · 0⤊ 0⤋
A) there are a total number of 67 students who are taking biology (this includes the number of students taking biology and chemistry). There are 200 students. 67 divided by 200 is 33.5%
B) The total number of students taking Chemistry is 70. The total number of students taking Physics is 110. 70 +110 = 180
minus the ones taking both 180 - 60 = 120 and 120 divided by 200 is 60%
2007-06-26 04:24:22 · answer #2 · answered by fangfarris 2 · 0⤊ 2⤋
a 67/200 = 33.5/100 = 33.5%
b 70 are in chemistry
. . 110 are in physics
. . .60 are in both
70 - 60 = 10 in only chem
110 - 60 = 50 in only physics
10 + 50 + 60 = 120
120 / 200 = 60 / 100 = 60%
2007-06-26 04:25:24 · answer #3 · answered by TychaBrahe 7 · 0⤊ 0⤋
b) P(chemistry or Physics)=P(chemistry)+P(Physics)-P(chemistry and physics)
=70/200+110/200-60/200
=120/200=60/100=0.6
a) 67/200
2007-06-26 04:55:08 · answer #4 · answered by cidyah 7 · 0⤊ 0⤋