help with math word problem?
2017-10-18 10:29 pm
Mark works out for 50 minutes by biking and jogging. He bikes at an average rate of 1200 feet per minute for x minutes. He jogs at an average rate of 900 feet per minute. He wants to travel a combined 10 miles. How many minutes did mark spend biking
回答 (1)
2017-10-18 10:34 pm
10 mi = 52800 feet
(1200 ft/min)x + (900 ft/min)y = 52800 ft
x + y = 50
1200x + 900y = 52800
divide by 300 to simplify
4x + 3y = 176
substitute y = 50 – x
4x + 3(50 – x) = 176
4x + 150 – 3x = 176
x = 26 min
y = 24 min
(1200 ft/min)x + (900 ft/min)y = 52800 ft
x + y = 50
1200x + 900y = 52800
divide by 300 to simplify
4x + 3y = 176
substitute y = 50 – x
4x + 3(50 – x) = 176
4x + 150 – 3x = 176
x = 26 min
y = 24 min
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