Tonya spent $90.00 on art supplies. 4 canvases cost $40.00 and a mixed set of paints cost 1/2 that much. She also spent $15.00 on an easel, and the rest of the money on paintbrushes. How much money did she spend on paintbrushes? Let's think first. Chain of thought:
The canvases cost $40.00 and she spent half that amount on paint so she spent 40 / 2 = $20.00 on paint. She spent $40.00 on canvases, $20.00 on paint and $15.00 on an easel so she spent 40 + 20 + 15 = $75.00. She spent $90.00 total and her other purchases totaled $75.00 so she spent 90 - 75 = $15.00 on paint brushes.
Therefore, the answer is 15.