Another problem on Estimation

Please help me to solve the following problem.

A computer in adding numbers, rounds each number to the nearest integer. All the rounding errors are independent and come from a uniform distribution over the range [-0.5,0.5].

Find how many numbers can be added together so that the probability that the magnitude of the total error is less than 10 is at least 0.95.

Another problem on Estimation

I get it.

So the rest have to be done as follows

P(-10/RT(n/12) < Z < 10/RT(n/12) >=0.95

ie -1.96 < Z < 1.96

so 10/RT(n/12) = 1.96

n=312

Thanks very much.