Transcript D 1 = D 2 D 1 D 2

Warmups
Solve for x.
3 x  y  4m
3x  b
2a 
y
Fifteen decreased by some number is 34. Find the number.
a) Define a variable, b) write an equation, and c) solve
a)
b)
c)
Distance Story
Problems
Notes are on a
worksheet today!
Steps – write on back of notes paper.
1) Draw a picture
d1 + d2 = dTotal
x
x
x
x–5
x
5–x
5 hrs
later
5 hrs
total
Same
time
2) Fill in the box
r ∙ t = d
D1 = D2
3) Write an equation
4) Solve the equation
5) RE-READ THE QUESTION!
1. Two jets leave Washington, D.C., at the same time, one
traveling north at 850 km/h and the other traveling south at
750 km/h. In how many hours will they be 4800 km apart?
d1 + d2 = dTotal
r
N
S
∙
t
=
d
850
x
850x
750
x
750x
850x  750x  4800
1600x  4800
x3
Answer: 3 hours
2. Jeanne and Teresa leave their campsite and paddle their canoe
down a river at a constant rate of 6 km/h. Four hours later, Mei Ling
leaves the campsite in a motorboat and travels down the river with the
camping supplies. If the motorboat travels at 18km/h, how long does it
take to overtake the canoe?
D1 = D2
r
C
M
∙
t
=
d
6
x
6x
18
x–4
18(x – 4)
6 x  18  x  4
6x  18x  72
12x  72
x6
Answer: 2 hours
3. Walt rode his bike from home to the bicycle repair shop and then
walked home. He averaged 18 km/h riding and 6 km/h walking. If his
total travel time was one hour, how far is the shop from Walt’s home?
D1 = D2
r
∙
t
=
d
D1
18
x
18x
D2
6
1–x
6(1 – x)
18x  6 1  x 
18x  6  6x
24x  6
1
x
4
Answer: 4.5 hours
Homework
What Kind of Car does a Baker Drive?