The clue is in the words 'at least' and 'at most'
'at least 0.355 inch' means the diameter can't go lower than 0.355
'at least 0.375 inch' means the diameter can't go over 0.375
'at least 0.355-inch' means d ≥ 0.355
'at most 0.375 inch' means d ≤ 0.375
Put them together 0.355 ≤ d ≤ 0.375