Rate of change-planes

D

DanaAJames

New member
Joined
Oct 29, 2014
Messages
22
"Two planes leave a city for another city that us 600 miles away. One of the planes is flying 50 miles per hour faster than the other. The slower plane takes 2 hours longer to reach the city. What is the rate of each plane? Write and solve a system of equations."


I am pretty sure that the equations are 600=rt, and 600=(t+2)(s-50), if r represents rate, t representstime iand s represents speed. But, I also know that if 600=rt, then r=600/t. So, I can replace r with 600/t. So my equations are 600=(600/t)t, and 600=(t+2)(s-50).

Am I correct so far? Also, how do I solve from here? Thanks!
 
DanaAJames said:
"Two planes leave a city for another city that us 600 miles away. One of the planes is flying 50 miles per hour faster than the other. The slower plane takes 2 hours longer to reach the city. What is the rate of each plane? Write and solve a system of equations."

I am pretty sure that the equations are 600=rt, and 600=(t+2)(s-50), if r represents rate, t representstime iand s represents speed.
Click to expand...
What is the difference between "rate" and "speed"? ;)
 
You're on the right track about making two equations though. You want to have 600 = something, and 600 = something else. However, your first equation is meaningless. Multiply it out and you'll see why...

600 = (600/t)*t --> 600 = 600t / t --> 600 = 600

Think about the relationship between the two planes speeds and between their times. We have the following information:

s1 = Speed of slower plane
s2 = s1 + 50 = Speed of faster plane

t1 = t2 + 2 = Travel time of slower plane
t2 = Travel time of faster plane

You know that Distance = Speed * Time, so you should be able to easily make two equations.
 
You must log in or register to reply here.
Top