Answer:
reorder point = 132.67 ≈ 133 units
Step-by-step explanation:
z score for service level 90% = 1.28
lead time = 6 days
mean demand 60 units for 3 days period, 20 per day
standard deviation of demand = 7 units
reorder point = (20 x 6) + {1.28 + √[(7x7)/3] x √6} = 120 + 12.67 = 132.67 ≈ 133 units