Dennis and Chris Reed leave simultaneously from the same point hiking in opposite directions, Dennis is walking at 4 miles per hour and Chris at 2 mph. How long can they talk on their walkietalkies if the walkietalkies have a 15 mile radius?
Distance = rate x time d = rt Dennis rate = 4 time = t {left at same time} d = 4t {distance = rate x time} Chris rate = 2 time = t {left at same time} d = 2t {distance = rate x time} Combined distances must be no more than 15 miles. 4t + 2t = 15 {added distances and set equal to 15} 6t = 15 {combined like terms} t = 2.5 hours {divided each side by 6} 0.5 hours is 30 minutes. They can talk for 2 hours and 30 minutes, or 2.5 hours as requested for rounding. Ask Algebra House Comments are closed.

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