It’s about add and subtract so whats 1-3/8
1 answer:
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Answer:
8%
Step-by-step explanation:
Hello,
<u>8% of the students take neither History or French</u>
so we have 8*200/100=8*2=16 students out of French and History
let s say that
a is the number of students taking only History
b is the number of students taking both History and French
c is the number of students taking only French
<u>10% of those who take History also take French</u>
so 0.10(a+b)=b <=> 0.10a+0.10b=b
<=> 0.10a+0.10b-0.10b=b-0.10b=0.9b
<=> 0.10a=0.90b
let's multiply by 10 it comes a = 9b
<u>4 times as many students take History as take French</u>
so a + b = 4 (b + c)
it comes 9b + b = 10b = 4b + 4c
<=> 10b-4b=4b+4c-4b=4c
<=> 6b=4c
<=> 3b=2c
<=> c = 3b/2
and we know that a + b + c = 200 - 16 = 184
so
9b + b + 3b/2 = 184 we can multiply by 2 it comes
20 b + 3b = 184*2
23b = 184*2 = 23 * 8 *2 = 23*16
b = 23*16/23 = 16
so b = 16
c = 3*16/2 = 24
c = 24
a = 9b = 144
a = 144
you can see the Venn diagram below
and then the probability that a student picked at random does History and French is 16/200 = 8%
so the answer is 8%
hope this helps
