lois and clark leave thier office to meet clients lois leave

lois and clark leave thier office to meet clients. lois leaves at 8 am and travels at 35moh. clark leaves at 815am and travels at 40 miles an hour. they travel in opposite directions. when will they be 290 miles apart?

Solution

Lois DATA:
rate = 35 mph ; time = x hrs. ; distance = 35x miles
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Clark DATA:
rate = 40 mph ; time = x-(1/4) hr ; distance = 40(x-(1/4)) = 40x-10 miles
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Equation:
distance + distance = 290 miles
35x + 40x-10 = 290
75x = 300
x = 4 hrs
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290 miles apart at 8:00 + 4 hrs = 12:00 noon