Marlene rides her bicycle to her friend Jon's house and returns home by the same route. Marlene rides her bike at constant speeds of 6 mph on level ground, 4 mph when going uphill and 12 mph when going downhill. If her total time riding was 2 hours, how far is it to Jon's house?
Accepted Solution
A:
x = level groundy = hillsx/6 +y/4 +y/12 + x/6 = 2 hours multiply everything by 12 to get rid of the denominators: equation becomes 2x +3y +y +2x = 24 combine like terms:4x +4y = 24 divide everything by 4 f +h = 6 miles to Jon's house