akshdeep28 wrote:
ezhilkumarank wrote:
Financier wrote:
The 7th grade French and Spanish classes each have 15 students in them, and there are five students in the 7th grade taking both languages. If everyone in the 7th grade is in at least one of the two language classes, how many students are taking just one of the two classes?
5
10
15
20
25
Total = 15 students.
15 = n(F) + n (S) - n (AnB) + Neither
Neither F nor S is zero.
15 = (F - 5) + (S - 5) - 5
15 = (F + S) - 10 + 5
15 = (F + S) - 5
Hence (F+S) = 20. Answer choice D.
Can anyone tell me why we did't take total students 30 in number. As we have 15 students in each class. (15+15). getting confused
Hi
akshdeep28Let me answer your query with the help of Venn diagram
The question tells us that 15 students attend the French class and 15 students attend the Spanish class. There would have been a total of 30 students had there been no student who attends both French & Spanish classes. However we are given in the question that there are 5 such students who attend both the classes.
From the Venn diagram, we can say that b = 5
We are also told that 15 students attend French class, so we can write a + b = 15 which would give us a = 10 i.e. the number of students who attend only the French class.
Similarly b + c = 15 which would give us c = 10 i.e the number of students who attend only the Spanish class.
Hence the number of students who attend just one class = a + c = 20. Also, the total students would be a + b + c = 10 + 5 + 10 = 25
Hope it's clear
Regards
Harsh
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