Jack and Jill have a magic pail of beans. The number of beans in the pail doubles every second. If

Jack and Jill have a magic pail of beans. The number of beans in the pail doubles every second. If the pail is full after 10 seconds, when was the pail half full? Explain your answer.

• At time 0, we have n beans
• At time 1, we have 2n beans
• At time 2, we have 4n beans
• At time 3, we have 8n beans
• At time 4, we have 16n beans
• At time 5, we have 32n beans
• At time 6, we have 64n beans
• At time 7, we have 128n beans
• At time 8, we have 256n beans
• At time 9, we have 512n beans
• At time 10, we have 1024n beans

1/2 of 1024 is 512, so at Time 9, the pail is half full.