Question 395789
A coin collector bought a new coin worth 3 times the average value of the other 17 coins in his collection. What part of the value of the total collection does the new coin represent?

let x=average value of the 17 coins in the current collection
3x=value of new coin

part value of new coin =3x/(17x+3x)
=3x/x(17+3) =3/20 or 15%

ans: the new coin represents 15% of the total collection