Mike scores average of 21 in 7 math tests. His average in the first 3 tests is 19. What is his average in the last 4 tests?

**(A)** 22

**(B)** 22.5

**(C)** 23

**(D)** 23.5

**(E)** None of the above

It is given to us that average is 21 in 7 math tests.

**(1)**

It is also given to us that average in the first 3 tests is 19.

**(2) **

Putting **(2)** in **(1)**, we get

Hence, the answer is **(B)**.