If they paid $0.72 in tax and tax is 6% or .06 then you could create an equation like this: x * .06 = .72 with x representing the original cost of the bracelet. Now you can just solve for x like so:
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.