College algebra word problem any help?
1.) A cleaning company has monthly fixed costs of $9000 for its facilities and it costs $100 per house for each house that it cleans. How many houses must the company clean each month to have an average cost per house of $170?
2.) A c a r t r a v e l s 4 0 0 m i l e s o n l e v e l t e r r a i n i n t h e s a m e a m o u n t o f t i m e i t t r a v e l s 1 6 0 m i l e s o n m o u n t a i n o u s t e r r a i n. If the rate of the car is 30 miles per hour less in the mountains than on level ground, find its rate in the mountains.
Comments
1.) A cleaning company has monthly fixed costs of $9000 for its facilities and it costs $100 per house for each house that it cleans. How many houses must the company clean each month to have an average cost per house of $170?
Let x = number of houses
170x = 9000 + 100x
70x = 9000
x =128.57 >>>129 houses
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2.) A c a r t r a v e l s 4 0 0 m i l e s o n l e v e l t e r r a i n i n t h e s a m e a m o u n t o f t i m e i t t r a v e l s 1 6 0 m i l e s o n m o u n t a i n o u s t e r r a i n. If the rate of the car is 30 miles per hour less in the mountains than on level ground, find its rate in the mountains.
x = rate on mountain terrain
x + 30 on level ground
400/(x + 30) = 160/x
400x = 160(x + 30)
400x = 160x + 4800
240x = 4800
x = 20 mpx
average cost = (9000 + 100x)/x
solve for x