Who's seen "The Life of Pi" and "Finding Nemo?"

Hello,easy 1,

as total students=x,

so,

20 +( 20/100).x = x

20 + (1/5).x=x

20(5) + x = 5x

4x=100 x=100/4=25...

thanks...

SAY, STUDENTS NUMBER IS X. X/5 STUDENTS DIDN'T WATCH ANY MOVIES.SO ,4X/5 STUDENTS WATCH THE MOVIE.SO, 4X/5=20 AND X=25

Draw a venn diagram with the class as the universal set and the people who have watched the movies as 2 sets.... It will make things simple. Answer is 25.

Let n be the total number of students in the class. Since we know that 20% of the total number of students haven't seen either movie, we can conclude that 80% of the total number of students have seen at least one movie.

We know that 20 students (or 80% of the total) had seen at least one of the movies: $n \times 0.8 = 20$ But we want to know how many total students there are, so we need to solve for n .

First we divide both sides by 0.8 : $\frac{n \times 0.8}{0.8} = \frac{20}{0.8}$ Which simplifies to: $n = \frac{20}{0.8}$ 0.8 can be written as $\frac{80}{100}$ so if we substitute it in, we get $n = \frac{20}{\frac{80}{100}}$ or $n = 20 \times \frac{100}{80}$ This simplifies to $n = 1 \times \frac{100}{4}$

This simplifies and we get $n = \boxed{25}$

This problem is simple set theory problem . Say A and B are two movies then
n(A) - n( $A \cap B$ ) = no. of students seen movie A
n(B) - n( $A \cap B$ ) = no. of students seen movie B
Thus, n(A) + n(B) - 2 $\times$ n( $A \cap B$ ) = no. of students seen at least movie A or B
n( $A \cap B$ ) = no. of students seen both movies A and B
and n( $A \cup B$ ) = total no. of students

Let total no. of students = N, then
n( $A \cup B$ ) = N
and n( $A \cap B$ ) = N / 5
also n(A) + n(B) - 2 $\times$ n( $A \cap B$ ) = 20

As n( $A \cup B$ ) = n(A) + n(B) - n( $A \cap B$ )
$\Rightarrow$ n( $A \cup B$ ) = n(A) + n(B) - 2 $\times$ n( $A \cap B$ ) + n( $A \cap B$ )
Thus, N = 20 + (N / 5)
So, N = 25 .

let total no. of students be x.. since , 20 students were known. therefore, 20+20/100*x=25 there were 25 students in the class.....

20 students have seen at least one of the two movies, and 20% have seen neither the first nor the second. Which means that 20 constitutes 80% of the students of this class. If 20 is 80% the total number, then this total will be: 20+20/4=20+5=25

20% students are not watching film, and in 20 students at least one of them watching film,that means 80% students are watching film. and 80% is equals to 20 students, therefore, 20% is equals to 5 students. and finally 20 + 5 = 25 students.

it means 80% of student watch atleast 1of them so 80%of total student=2 the 20student so total student is 25

80% = 20 students who had watched movies ....

80/100 = 20

1/100 = 20/80 = 1/4

100/100 = 1/4 *100 = 25