Question

among the candidate appeared in a examination ,80% passed in English, 85% in maths and 75% in both English and math .find the total number of candidates,if 45 candidate were failed in both English and math8​

Answer 1

Answer:

Let the total number of student is x

Number of student passed in both subject is

n(A∪B)=n(A)+n(B)−(A∩B)

Here, n(A)=80% of x

n(B)=85% of x

n(c)=75% of x

∴n(A∪B)=  

100

80

​  

x+  

100

85

​  

x−  

100

75

​  

x

⇒  

100

90x

​  

⇒  

10

9x

​  

 

Failed in both subjects

⇒x−  

10

9x

​  

⇒  

10

x

​  

 

∴  

10

x

​  

=40

⇒x=400

ᴵᵀᶻ꧁ DISHANT⁰⁰⁷ ࿐    

Answer 2

Answer:

85 % passed in maths

75 % passed in both

And 45 students failed in both.

So, let there are X no of students.

80% of X passed in sub = (80/100)*x =4x/5.

85% of X passed in maths=(85/100)*x=17x/20.

75% of X passed in both =(75/100)*x= 3x/4.

There students passed “only” in sub = students passed in sub - students passed in both

i.e 4x/5 - 3x/4 = x/20 .

Similarly, students passed only in maths

= 17x/20 - 3x/4 = x/10 .

There for total students passed = 3x/4 + x/20 + x/10 = 18x/20 = 9x/10 .

There for no of students failed = x - 9x/10 = x/10

And x/10 = 45 ( given in question)

So X = 450 .

There total students in class is 450 .

Note : X =x.

Step-by-step explanation:

I hope it helps.