Answer:
30 m/s
Step-by-step explanation:
Let's say the distance from the first car to the intersection is x, and the distance from the second car to the intersection is y.
The distance between the cars can be found with Pythagorean theorem:
d² = x² + y²
Taking derivative with respect to time:
2d dd/dt = 2x dx/dt + 2y dy/dt
d dd/dt = x dx/dt + y dy/dt
We know that x = 200, dx/dt = -25, y = 150, and dy/dt = -50/3.
To find dd/dt, we still need to find d.
d² = x² + y²
d² = (200)² + (150)²
d = 250
Plugging everything in:
250 dd/dt = (200) (-25) + (150) (-50/3)
dd/dt = -30
The cars are approaching each other at a rate of 30 m/s at that instant.
Answer:
i hope its correct
Step-by-step explanation:
11x + 2y=68 ------------1
5x+y=13 ------------2
y= 13-5x. ------------3
put 3 into 1
11x +2(13-5x) =68
11x +26 -10x =68
x=42
put x =42 into 2
5(42) +y =13
210+y=13
y=13-210
y=197
Answer:
C
Step-by-step explanation:
.25x+.10y=$10
.25 because that is the value of the quarter, times x the number or quarters you have and .10 because that is the value of the dime times y, the number of dimes you have.
You would use the distributive property with the negative. So the second x becomes negative, but since the 7 is already negative it becomes positive. Think of it as if you put the two dashes together you can make a plus sign.
