What is the "x" for 0.8=400x; the answer .002 doesn't feel right

Question

what is 0.8=400x, my brain is focused on concepts. Is it 0.2%?

The actual problem is: "Material delays have routinely limited production of household sinks to 400 units per day. If the plant efficiency is 80%, what is the effective capacity?"

Answer 1

Yes, is 0.8 = 400x, then x = 0.002.  However. . .

.

I think the question should be "80% of what number is 400?"

"%" means /100

"of" means *

"what number" means x

"is" means =

80/100 * x = 400

x = 400 * 100 / 80

x = 500

If the plant was operating at 100% capacity, production would be 500 sinks per day.

Answer 2

If plant efficiency means they can only produce 80% of their maximum capacity of 400 units, the equation to solve this would be x = 80% of 400, which 0.8 * 400 = 320 units. At 100% efficiency they would produce 400 units, so they've lost 80 units because of reduced efficiency. If, however, their efficiency of 80% corresponds to the 400 units, then their effective capacity at 100% would be given by x in the expression 0.8x = 400. So x = 400/0.8 = 500. It depends how you read the question.