the equation to calculate compound percentage rate is :
A(t) = P(1+(r/n))^(nt)
In this case t is 18 years, we put rate (r), number of compounds per day.
A(18) = 10,000(1+(0.04/4))^(4*18)= 10,000(1.01)^72= $20,470.99
Child will receive $20,470.99 on it's 18 birthday.