Chapter 9 - Database Systems - Section 9.4 - Maintaining Database Integrity - Questions & Exercises - Page 437: 3

A balance of $\$100$ would result if the transactions were executed one at a time. A balance of $\$200$ would result if the first transaction were executed after the second transaction retrieved the original balance and before that second transaction stored its new balance. A balance of $\$300$ would result if the second transaction were executed after the first retrieved the original balance and before the first transaction stored its new balance.

A balance of $\$100$ would result if the transactions were executed one at a time. A balance of $\$200$ would result if the first transaction were executed after the second transaction retrieved the original balance and before that second transaction stored its new balance. A balance of $\$300$ would result if the second transaction were executed after the first retrieved the original balance and before the first transaction stored its new balance.