A student’s standardised mark on a class test was z = –1.7. The mean mark for the class is 55 and the standard
deviation is 2.85.
Their mark on the test was closest to
A. 49
B. 50
C. 53
D. 58
E. 60

The answer is 58, standard deviation is basically telling you that the space between each point in your statistics is on average that amount so that can tell us to take the mean mark of 55 and add 2.85 = 57.85