Armen is 30 years old now and hopes to retire when he is 60. He wants to invest $10,000 in an account so that the balance will be $50,000 when he retires. What annual percentage rate is necessary for this to happen? (assume that the interest is compounded annually)

Hector and alex traded video games. alex gave hector one fourth of his video games in exchange for 6 video games. then he sold 3 video games and gave 2 video games to his brother. alex ended up with 16 video games. how many video games did alex have when he started?