Final answer:
By setting up a directly proportional relationship between cookies and flour scoops, it's determined that Lacey will need 70 scoops of flour to bake 490 cookies.
Step-by-step explanation:
The student's question is about determining the amount of an ingredient based on a directly proportional relationship, which is a mathematical concept covered often in middle school. Lacey baked 140 cookies with 20 scoops of flour. To find out how many scoops of flour Lacey needs to bake 490 cookies, we can set up a proportion because the relationship is directly proportional:
140 cookies / 20 scoops of flour = 490 cookies / x scoops of flour
Cross-multiply to solve for x:
140x = 490 * 20
Then divide both sides by 140 to solve for x:
x = (490 * 20) / 140
x = 9800 / 140
x = 70 scoops
Therefore, Lacey needs 70 scoops of flour to bake 490 cookies.