JoAnne is depositing money into the bank account. After 3 months there is $150 in the account. After 6 months, there is $300 in the account. Find the constant rate of change of the account.

The constant rate of change for the account is +50.
If JoAnne started off with $150 at three months, she would go up by $50 each month after that to get to 300.
Month 4: 150+50=200
Month 5: 200+50=250
Month 6: 250+50=300