There are two boxes of masks *** 1000. Can I take 150 from the first box?

There are two boxes of masks *** 1000. If you take 150 from box a, you can.

It is feasible to take 150 masks from one box, because there are 1000 masks in two boxes, so taking 150 masks from one box will not lead to insufficient total. There will be 850 masks in the remaining boxes. This can meet your needs of taking out 150 masks.