a clothing store sells two types of t-shirts: plain and printed. plain t-shirts cost $10 each, and printed…

a clothing store sells two types of t-shirts: plain and printed. plain t-shirts cost $10 each, and printed t-shirts cost $15 each. the store sold a total of 30 t-shirts and made $380. how many plain and how many printed t-shirts were sold?
Answer
Explanation:
Step1: Define variables
Let $x$ = number of plain t-shirts, $y$ = number of printed t-shirts.
Step2: Set up total quantity equation
Total t-shirts sold: $x + y = 30$
Step3: Set up total revenue equation
Total money made: $10x + 15y = 380$
Step4: Isolate variable from first equation
Rearrange $x + y = 30$ to $x = 30 - y$
Step5: Substitute into revenue equation
Substitute $x = 30 - y$ into $10x + 15y = 380$: $10(30 - y) + 15y = 380$ $300 - 10y + 15y = 380$ $300 + 5y = 380$
Step6: Solve for $y$
$5y = 380 - 300$ $5y = 80$ $y = \frac{80}{5} = 16$
Step7: Solve for $x$
Substitute $y=16$ into $x = 30 - y$: $x = 30 - 16 = 14$
Answer:
14 plain t-shirts and 16 printed t-shirts were sold.
Completed Table:
| CLAIM | EVIDENCE | REASONING |
|---|---|---|
| 14 plain t-shirts and 16 printed t-shirts were sold. | Plain t-shirts: $10 each, printed: $15 each; 30 total t-shirts sold, $380 total revenue. | Define variables for each t-shirt type, set up system of equations for total quantity and revenue, substitute to solve for one variable, then find the second variable. Verify: $10(14) + 15(16) = 140 + 240 = 380$, and $14+16=30$, which matches the given totals. |