The cost of 5 similar digital cameras and 3 similar video cameras is 3213. Each video camera costs 4 times as much as each digital camera. John buys a digital camera and a video camera. How much does he pay?
[tex]x\ -\ cost\ of\ digital\ camera\\y\ -\ cost\ of\ video\ camera\\5x+3y=3213\\y=4x\\5x+3\cdot4x=3213\\17x=3213/:17\\x=189\\y=4\cdot189\\y=756\\\\189+756=945[/tex] Answer: John pays 945 for a digital camera with a video camera.
