Aldo is choosing between two exercise routines.
In Routine #1, he does only running, burning 8.5 calories per minute.
In Routine #2, he burns 21 calories walking. He then runs at a rate that burns 4.3 calories per minute.
For what amounts of time spent running will Routine #1 burn more calories than Routine #2?
Use t for the number of minutes spent running, and solve your inequality for t .