The question doesn't define the mean and standard in terms of what they represent, so I assume that 0.076 represents 7.6% and SD is 1.8%, meaning that the average percentage of those defaulting on loan is 7.6%. The z score of 10% defaulting is (0.10-0.076)/0.018=4/3 or 1.33 approx., which corresponds to a probability of 0.908, or 90.8% in a normal distribution. This means that 100-90.8%=9.2% is the probability that more than 10% default.