8. The number of dandelions growing on your lawn triples every 3 days. If your lawn started out with 15 dandelions, how many dandelions would you have after 3 weeks?

There will be 32805 dandelions after 3 weeks

Step-by-step explanation:

To determine number of dandelions after 3 weeks

1 week = 7 days

∴ 3 weeks = 3 × 7 days = 21 days

Hence, we will determine the number of dandelions after 21 days.

From the question,

The number of dandelions growing on the lawn triples every 3 days and if the lawn started out with 15 dandelions,

Then, After 3 days, there will be 3 × 15 dandelions = 45 dandelions

After 6 days, there will be 3 × 45 dandelions = 135 dandelions

After 9 days, there will be 3 × 135 dandelions = 405 dandelions

After 12 days, there will be 3 × 405 dandelions = 1215 dandelions

After 15 days, there will be 3 × 1215 dandelions = 3645 dandelions

After 18 days, there will be 3 × 3645 dandelions = 10935 dandelions

After 21 days, there will be 3 × 10935 dandelions = 32805 dandelions

Hence, there will be 32805 dandelions after 3 weeks.