Any ideas on where to start on converting these to a standard z score?

#1
Lewis earned 85 on his biology midterm and 81 on his history midterm. In the biology class the mean score was 79 with standard deviation 5. In the history class the mean score was 76 with standard deviation 3.

a) Convert each midterm score to a standard z score.
b) On which test did he do better compared to the rest of the class?
 
#2
Lewis earned 85 on his biology midterm and 81 on his history midterm. In the biology class the mean score was 79 with standard deviation 5. In the history class the mean score was 76 with standard deviation 3.

a) Convert each midterm score to a standard z score.
b) On which test did he do better compared to the rest of the class?

Z-score = (score - mean) / Standard Deviation Sooo..

Biology: (85 - 79) / 5 = 1.2
History: (81 - 76) / 3 = 1.67

The higher the z-score the better he did.