Marta's customer bought 4 large oranges at $0.75 each and 8 small oranges at $0.50 each plus tax was a total of $7.49. She used t to represent the amount of tax. Explain her errors in the diagram.

Given:

4 large oranges @ 0.75 each

8 small oranges @ 0.50 each

total amount paid: 7.49 including sales tax.

4 (0.75) = 3.00

8 (0.50) = 4.00

3 + 4 = 7

7 + t = 7.49

t = 7.49 - 7

t = 0.49 total amount of tax paid.

0.49/7 = 0.07 sales tax rate

the sales tax rate is 7%

4 (0.75) + 8 (0.5) = 7

7 x 0.07 = 0.49

7 + 0.49 = 7.49