Question 68905
I agree with your answer.  
I used the quadratic formula to solve for x.
Let 0=–16t^2+60t+9
Solve by using the quadratic formula:
x=-.144 or x= +3.894436803.  
Eliminate the negative answer.  
Rounding the positive answer = 3.894
Check by plugging 3.894 back into the original equation.
The answer is very close to zero (.028224), so it checks out.
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