Question

Problem: Tina bought some nail polish and lip gloss at the store. The nail polish cost $4.50 per bottle and lip gloss cost $7 per tube. Tina bought 9 items and spent $50.50. How many of each item did she buy?
Use this 4-step plan to answer the problem above!

Step 1: Understand. What are the facts? What are you asked to find? Is there any information you will not use?
Step 2: Plan: How will you solve this problem? State which strategy you are choosing to use.
Step 3: Solve. Show your steps. What is the solution?

Step 4: Check: Also include your check. Does your answer make sense?

Answer 1

a - number of nail polish bottles
b - number of lip gloss tubes
a+b=9    => b=9-a
4.50*a+7*b=50.50
4.50*a+7*(9-a)=50.50
4.50*a+63-7a=50.50
63-50.50=7a-4.50a
2.50a=12.50
a=12.50/2.50
a=5 nail polish bottles
b=9-a=9-5
b=4 lip gloss tubes

Answer 2

4.50x + 7x= $50.50
you will use Guess and check as a strategy
 4.50(5) +7(4) = 50.50

yes the answer does make sense