Question 920275: Adam made a trip to see his college friend. The college is 295 miles
from Adam's house. He averaged 50 miles per hour (mph)) for most of
the trip but only 40 mph for the part where the road was under
construction. If the trip took 6 hours, how many miles of the road
were under construction?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Adam made a trip to see his college friend. The college is 295 miles
from Adam's house. He averaged 50 miles per hour (mph)) for most of
the trip but only 40 mph for the part where the road was under
construction. If the trip took 6 hours, how many miles of the road
were under construction?
-----------------
1st part DATA:
rate = 50 mph ; distance = x miles ; time = d/r = x/50 hrs
------------------
2nd part DATA:
rate = 40 mph ; distance = 295-x miles ; time = d/r = (295-x)/40 hrs
-----
Equation:
time + time = 6 hrs.
x/50 + (295-x)/40 = 6
-----------------------
40x + 50(295-x) = 6*50*40
40x + 50*295 - 50x = 300*40
----
-10x = -2750
-----
x = 275 miles
295-x = 295-275 = 20 miles (road under construction)
-----------------------
Cheers,
Stan H.
-----------------------------------------------
|
|
|
