Question

Each student in the class sends new year greeting card to every one of his classmate, the total number of cards sent out will be 870. Find the number of student in the class . Also explain it step by step.​

Answer 1

Answer:

Answer is below:

Step-by-step explanation:

THE FORMULA FOR THIS PROBLEM IS:

N(N-1)=870

N^2-N-870=0

(N-30)(N+29)=0

N-30=0

N=30 ANSWER FOR THE NUMBER OF CLASSMATES.

Answer 2

Answer:

30 students.

Step-by-step explanation:

Let there are n students in class

So each student send greeting cards to (n-1) student

(Since he cannot send card to himself)

And there are n students so total number of cards are n(n-1)

According to question total number of card is given as 870

So

n×(n-1)=870

n× (n-1)= 30×29

so n=30.

Hope you understand my friend.