Question

90 gifts were distributed in a party every presented a gift to another how many persons were there in the party

Answer 1

Step-by-step explanation:

No. Of People be x

Each person would have to give one person a gift=(n-1)

But this would count every given gift as twice. So for equity we would divide whole by 2

A/C to que_

n(n-1)/2=90

(n^2-n)/2=90

n^2-n=180

n^2-n-180=0

n=<-(-1)±root{(1)^2-4×1×(-180)}>/2×1

n=<1+root{1+720}>/2 & <1-root{1+720}>/2

n=<1+26.8>/2 & <1-26.8>/2

n=27.8/2 & -25.8/2

n=13.9 & -12.8

n≠-12.8 because no. Of people can't be -ve

Hence n=13.9≈14 people were there in party