Answer
About 5,000 database reads/s. In review, anything from 3,330 to 7,500 counts as right.
The worked estimate
Misses are 100% − 95% = 5%. 100,000 × 0.05 = 5,000 reads/s. If the hit rate drops to 90%, misses double to 10,000/s: the database is sized by the miss rate, so a small drop in hit rate can overload it.
Numbers: Numbers to know.