5 years, 7 months ago
5 years, 7 months ago
Avg of father and mother=45
here total sum=45×2=90
when daughter is included avg is 35
so after including ,the sum is= 35×3=105
so daughter age is=105 - 90=15
5 years, 7 months ago
the AVG. age of parents = (x+y/2)=45
x+y =90
given that (x+y+z/3)=35
x+y+z=105
WKT x+y=90
z=105-90=15