Q: You have £40. Each pencil costs £2, and each eraser costs £3. If you buy 6 pencils and 3 erasers, how much money will you have left?
Feedback: Not quite! The equation formed here is: $2x + 3y = 40$, where $x$ is the number of pencils and $y$ is the number of erasers. Buying 6 pencils and 3 erasers gives us $2(6) + 3(3) = 12 + 9 = 21$. So, you've spent $21. Subtracting this from your total, $40 - 21 = 19$, meaning you have £19 left.
Feedback: Well done! The equation formed here is: $2x + 3y = 40$, where $x$ is the number of pencils and $y$ is the number of erasers. Buying 6 pencils and 3 erasers gives us $2(6) + 3(3) = 12 + 9 = 21$. So, you've spent $21. Subtracting this from your total, $40 - 21 = 19$, meaning you have £19 left.