At an annual function of a school ,each student gives gift to every other student . If the number of gifts is 1980 , find the number of students.
siddhartharao77:
I think 45
ya but hoe
how
Answers
Answered by
187
Let the number of students be x.
Given that each student gives a gift to every other student.
That means the number of ways in which each child gives a gift to every other child = x(x - 1).
Given that total number of gifts = 1980
x(x - 1) = 1980
x^2 - x = 1980
x^2 - x - 1980 = 0
x^2 - 45x + 44x - 1980 = 0
x(x - 45) + 44(x - 45) = 0
(x + 44)(x - 45) = 0
x = 45 (or) x = -44.
Since x cannot be -ve, So x = 45.
Therefore the number of students = 45
Hope this helps!
Given that each student gives a gift to every other student.
That means the number of ways in which each child gives a gift to every other child = x(x - 1).
Given that total number of gifts = 1980
x(x - 1) = 1980
x^2 - x = 1980
x^2 - x - 1980 = 0
x^2 - 45x + 44x - 1980 = 0
x(x - 45) + 44(x - 45) = 0
(x + 44)(x - 45) = 0
x = 45 (or) x = -44.
Since x cannot be -ve, So x = 45.
Therefore the number of students = 45
Hope this helps!
lines 4,5,6
What happened?
explain
Each children gives a gift to other children.
hence no of gits when x children are present = x*(x-1)
1980 = x(x - 1)
1980 = x^2 - x
hence no of gits when x children are present = x*(x-1)
1980 = x(x - 1)
1980 = x^2 - x
sry could not understand
Actually tell me what is ur doubt?>
i could not understand what number of ways
thanks again
Answered by
6
The number of students will be= 45
Similar questions