Out of 960 calculators, 8 were found be to defective
Probability:

0.00833...
As a Percent:
0.00833....× 100
0.833%
To the nearest tenth of percentage:
0.833% ≈ 0.8%
Answer:
Shes needs to work 26.67 hours
Step-by-step explanation:
In order to find the amount of time she needs to work, we need to divide the total by the rate that she earns money at. She needs a total of $400 and she gets 15 every hour.
400/15=26.67
Shes needs to work 26.67 hours