Marjorie works as a baker. Every day, she makes twice as many cakes as she did the day before. On the sixth day, she makes 320 cakes. How many cakes did Marjorie make on the first day?
Let's think: As the number of cakes doubles each day, Marjorie must have made 320 cakes / 2 = 160 cakes on the fifth day. So on the fourth day, she must have made 160 cakes / 2 = 80 cakes. This means that on the third day, she made 80 cakes / 2 = 40 cakes. On the second day, she made 40 cakes / 2 = 20 cakes. So on the first day, she made 20 cakes / 2 = 10 cakes.. The answer is: 10.

Carol has $60 and saves $9 per week. Mike has $90 and saves $3 per week. How many weeks before Carol and Mike both have the same amount of money?
Let's think: Let x = the number of weeks. 60 + 9x = 90 + 3x to set them equal. 9x = 30 + 3x. 6x = 30. x = 5. In 5 weeks they will have equal money.. The answer is: 5.

Mr. Johnson is organizing the school Christmas play and needs 50 volunteers to help with decorating the auditorium. 5 students from each of the school's 6 math classes have volunteered to help. 13 teachers have also volunteered to help. How many more volunteers will Mr. Johnson need?
Let's think: Since 5 students from each of the 6 math classes have volunteered, there are 5 * 6 = 30 total student volunteers. In addition to the 30 student volunteers, 13 teachers have also volunteered so there are 30 + 13 = 43 total volunteers. Mr. Johnson needs 50 volunteers and currently has 43 volunteers, so he needs 50 - 43 = 7 more volunteers.. The answer is: 7.

Oliver has 10 $20 and 3 $5 bills. William has 15 $10 and 4 $5 bills. How much more money does Oliver have than William?
Let's think:
Oliver's $20 bills amount to $20 x 10 = $200. Oliver's $5 bills amount to $5 x 3 = $15. So, Oliver has a total of $200 + $15 = $215. William's $10 bills amount to $10 x 15 = $150. William's $5 bills amount to $5 x 4 = $20. So, William has a total of $150 + $20 = $170. Therefore, Oliver has $215 - $170 = $45 more than William.. The answer is: 45.