Answer: 749 units
Explanation:
The formula for the Re-Order Point is;
ROP = d(LT) + z√( LTσd²+ d² σLT²)
Where,
d is demand
LT is lead time
σd is standard deviation of daily demand
σLT is standard deviation of lead time
As the stockout risk is to be 10%, z will be a service level of 90% which is ±1.28
ROP = 80(10) + 1.28√( 8(10)²+ 80² * 1²)
= 800 + 1.28√( 800 + 6400)
= 748.61
= 749 units