Answer:
975 bulbs
Explanation:
1/40 bulbs were defective
That means 1-1/40 were not defective
40/40 - 1/40 = 39/40 were not defective
We have 1000 bulbs
Multiply the number of bulbs by the fraction that is not defective to get the number of bulbs that should not be defective.
1000 * 39/40 = 975 bulbs