Depends what Ferrari car it is.
To write .0487 as a percent, you have to remember that 1 equal's100% and what you need to do is.. multiply the number by 100 and add the symbol % .
.0487 * 100 = 4.87%
For this question, you just divide 2400 by 400 and get how many days it'll take! which, is 6
The probability of finding one of the two defective fuses is:

The probability of finding 2 defective fuses is:

Therefore the probability of rejecting is 0.3117 + 0.026 = 0.3377.