Mrs. McKay opened an account with a deposit of $2,000. The account earned annual simple interest at a rate of 3.5%. She did not make any additional deposits or withdrawals and earned $280 in interest. How many years did Mrs. McKay have her money in the account?

If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.