To solve this problem, you simply need to know how much the cell phone company charges per minute. If we know that it costs $15.00 for 170 minutes, then that means that one minute costs roughly 0.09. That figure is derived by simple division ($15.00/170)=$0.09.
Now that we know that one minute costs $0.09, we know that 1983 minutes will cost $178.47. That figure is derived by multiply $0.09 x 1983