7 t-shirts and a hat costs £67.00 5 t-shirts and a hat costs £49.00. How much does a t-shirt cost? How much does a hat cost?
+26367 7 t-shirts and a hat costs £67.00
5 t-shirts and a hat costs £49.00.
How much does a t-shirt cost?
How much does a hat cost?
Let t-shirt \(= x \)
Let hat \(= y\)
\(\begin{array}{|lrcll|} \hline (1) & 7x+y &=& 67 \\ (2) & 5x+y &=& 49 \\ \hline (1)-(2): & 7x+y -(5x+y) &=& 67-49 \\ & 7x+y -5x -y &=& 18 \\ & 7x -5x &=& 18 \\ & 2x &=& 18 \quad | \quad :2 \\ & \mathbf{x} &=& \mathbf{9} \\ \hline & 5x+y &=& 49 \quad | \quad \mathbf{x=9} \\ & 5*9+y &=& 49 \\ & 45 + y &=& 49 \\ & y &=& 49-45 \\ & \mathbf{y} &=& \mathbf{4} \\ \hline \end{array}\)
A t-shirt does \(\mathbf{£9.00}\) cost?
A hat does \(\mathbf{£4.00}\) cost?
