Question

John and Maria leave town in separate cars from the same location at the same time traveling in opposite directions. John drives 55mph while maria drives 40mph. how long will it take for them to be 228 miles apart?

Answer 1

h is the time.

John's distance increased by 55 miles each hour. Maria's increases by 40 miles each hour.
We can translate that into the equation of a line.
y=55h+40h
The specific value we want is 228.
228=55h+40h
228=95h
h=2.4 hours

Answer 2

yes

Answer 3

P (total principal) = 12000
RA (rate of stock A) = 4%
RB (rate of stock B) = 5%
I (total interest) = 550
IA (interest of stock A) = ???
IB (interest of stock B) = ???

These are the values

Answer 4

yes i know

Answer 5

i=prt

IA=PA*0.04*1
IB=PB*0.05*1

IA+IB=550
0.04PA+0.05PB=550

Answer 6

where PA=principal of stock A, PB=principal of stock B, etc etc

Answer 7

0.04PA+0.05PB=550

PA+PB=P
PA+PB=12000
PA=12000-PB
and we substitute this into the original

0.04(12000-PB)+0.05PB=550
480-0.04PB+0.05PB=550
combine like terms
0.01PB=70
PB=7000

P=PA+PB
12000=PA+7000
5000=PA

There you go. $5000 in the first, $7000 in the second. The magic of systems of equations.

Answer 8

thanks!!!!