Which of the following situations represents a variable rate of change? Group of answer choices Over a 10-year period, the number of children in the Wilcox family increased by 1 child every 2 years. Douglas ran a 5K race with an average pace of 7 minutes per mile. Hannah invested $2000 in a savings account that earns 2.1% compound interest per year. Blake saved $100 a month for one year in order to purchase a new TV with cash. Anna works at BYUI and has a starting pay of $8.85. Each semester that she works, she will earn a 10-cent raise