I saw one question regarding Z test (Que.3) in this article

**A test is administered annually. The test has a mean score of 150 and a standard deviation of 20. If Ravi’s z-score is 1.50, what was his score on the test?**

A) 180

B) 130

C) 30

D) 150

E) None of the above

I am not able to understand the explanation for the answer. Can someone please explain how the answer is A. I have the idea about the z test and its formulation.

Thanks