SOLUTION: A car travels 355 miles by going one speed for 3 hours and another speed for 4 hours. if it travels 3 hours at the second speed and 4 hours at the first speed, it would have gone 3

Question 1049373: A car travels 355 miles by going one speed for 3 hours and another speed for 4 hours. if it travels 3 hours at the second speed and 4 hours at the first speed, it would have gone 345 miles. find the two speeds.
Found 2 solutions by jorel555, advanced_Learner:
Answer by jorel555(1290) (Show Source): You can put this solution on YOUR website!
Let m be the first speed, and n be the second. Then:
3m+4n=355
4m+3n=345. So:
16m+12n=1380
9m+12n=1065
7m=315
m=45 mph
n=55 mph. ☺☺☺☺

Answer by advanced_Learner(501) (Show Source): You can put this solution on YOUR website!
the equations are
=
=

Solved by pluggable solver: SOLVE linear system by SUBSTITUTION

Solve:
We'll use substitution. After moving 4*y to the right, we get:
, or . Substitute that
into another equation:
and simplify: So, we know that y=55. Since , x=45.

Answer: .

RELATED QUESTIONS
A car travels for 3 hours at an average speed of 50 miles per hour. How far has it... (answered by jim_thompson5910)
a car travels 158 miles in 3 hours find the avg speed if the car in feet per second (answered by ankor@dixie-net.com)
If a car travels 250 miles in 7 hours, what speed is it... (answered by oberobic)
If a car travels 60 miles in 3 hours, what is the car�s... (answered by ewatrrr)
For a car moving at a constant speed, the distance traveled varies directly with the time (answered by Boreal)
a car travels 2 3/4 hours at an average speed of 60 km/hour and then for 2 1/4 hours at... (answered by mananth)
A car travels for 3 hours at a speed of 55 miles per hour and then for the next 2 hours... (answered by ikleyn)
if A car travels at an average speed of 68 miles per hour . How many miles does it travel (answered by richwmiller,josmiceli)
A car travels 100 miles to city A in 2 hours, and then travels 200 miles to city B in 3... (answered by ewatrrr)