Answer: Our required probability is 0.3162.
Step-by-step explanation:
Since we have given that
n = 60
Probability of success = 
Probability that at most 39 of these relays come from supplier A would be

Hence, our required probability is 0.3162.
5.476 rounded to the hundrdths is
5.48
2nd attempt carries a price of 6% extra, so (6/100) * 548 is 32.88, so 548 + 32.88, the price is 580.88.
for the 3rd attempt 6% extra of that, (6/100) * 580.88, is 34.8528, so the price is 615.7328.
4th attempt is 6% extra of that, (6/100) * 615.7328, 36.943968, adding that will give us 652.676768.