Answer:
The speed of the first car is 60 mph
Step-by-step explanation:
speed = distance/time
Solve the above equation for distance to get
distance = speed * time
or simply
d = st
Now we use this formula for distance to write an equation for each car.
Let s = speed of second car
Then since the speed of the first car is 10 mph faster, the first car's speed is s + 10.
The time the two cars traveled is equal but unknown, so let the time = t.
First car: speed = s + 10; time = t; distance = 120 miles
d = st
120 = (s + 10)t
(s + 10)t = 120 Equation 1
Second car: speed = s; time = t; 100 miles
d = st
100 = st
st = 100 Equation 2
Equations 1 and 2 form a system of 2 equations in 2 unknowns.
(s + 10)t = 120
st = 100
Distribute t in the first equation.
st + 10t = 120
From the second equation we know st = 100, so substitute 100 for st.
100 + 10t = 120
10t = 120
t = 2
The time traveled was 2 hours.
Equation 2:
st = 100
Substitute t with 2.
s * 2 = 100
s = 50
The speed of the second car was 50 mph.
The speed of the first car is s + 10.
s + 10 = 50 + 10 = 60
Answer: The speed of the first car is 60 mph
Answer:
5
Step-by-step explanation:
The slope is given by
m = (y2-y1)/(x2-x1)
-3/10 = (-5--8)/(-5-x)
-3/10 = (-5+8)/(-5-x)
Using cross multiplication
-3 (-5-x) = 10*(-5+8)
Simplify
-3(-5-x) =10(3)
Divide by -3
-3/-3(-5-x) =10(3)/-3
-5-x = -10
Add 5 to each side
-5-x+5 = -10+5
-x=-5
Divide by -1
x=5
Answer:
4i
Step-by-step explanation:
-4i(2+3i)
-8i-12i
4i
Answer:
meter
Step-by-step explanation:
We have to write first what is known from the information.
Let's say, length is L, width is W, and height is H
1. The length of the box is 2 1/2 m = 2,5 m = 5/2 m, it is 1 9/16 = 25/16 times it's width (L). So we have the equation :
L ≡ 
Then we find the W. From the fraction above, we found W equals to 
meter
2. What is the height of the box, if its volume is 12 3/4 m^3 = 51/4 m^3
Formula of a volume is :
The area wide times the height
In this problem, the equation is :
L × W × H = Volume
Insert the numbers,
× 
× H = 
From the fraction above, we can find that H equals to
meter
