2
algebra

Two runners start at the same point running in opposite directions. Runner A runs at 6 mph, Runner B at 8 mph. After how many hours will they be 21 miles apart?

A

1.25 hours

B

1.5 hours

C

1.75 hours

D

2 hours

Correct Answer: B

Choice B is the correct answer. Opposite directions → add speeds.

Let tt = time in hours.

Combined separation rate: 6+8=146 + 8 = 14 mph

Equation: 14t=2114t = 21t=1.5t = 1.5

Solution: 1.5 hours

Verification: In 1.5 hours: 6(1.5)+8(1.5)=9+12=216(1.5) + 8(1.5) = 9 + 12 = 21 miles ✓

💡 Strategic Tip: Opposite directions → distances add up.

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Linear Functions Set 59