Thread: Assistance on Algebra word problem

Anklescratch County and Kneebend County are two adjacent counties. In Anklescratch County, 30% of the miles of road have bike lanes, whereas in Kneebend County, only 10% of the miles of road have bike lanes.


A. Elliot say that in the two-county area, 40% of the miles of road have bike lanes. Elliot found 40% by adding 30% and 10%. Is she correct?

B.What percent of miles of road in the two-county area have bike lanes if Anklescratch County has 200 miles of road and Kneebend County has 800 miles of road? What if it's the other way around and Anklescratch County has 800 miles of road and Kneebend County has 200 miles of road?

C.Ming says that 20% of the miles of road in the two-county area have bike lanes because 20% is the average of 10% and 30%. Explain why Ming's answers could be either correct or incorrect. Under what circumstances will Ming's answer be correct

Let total roads be 100 miles in each country
Anklescratch County has 30 miles bike lanes
and Kneebend County has 10 miles bike lanes
consider both countries total roads = 100 + 100 = 200 miles
total bike lanes = 30 + 10 = 40 miles
% = 40/200 × 100 = 20 % and not 40%

In Anklescratch County has 200 × 0.30 = 60 miles bike lanes
and Kneebend County has 800 × 0.1 = 80 miles bike lanes
consider both countries total roads = 200 + 800 = 1000 miles
total bike lanes = 60 + 80 = 140 miles
% = 140/1000 × 100 = 14 %
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