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:
120
Step-by-step explanation: because you add 20 twice and thts 40 and 40 times 3 is 120
Answer:
Sample size should be atleast 617
Step-by-step explanation:
given that a 95% confidence interval for the mean of a population is to be constructed and must be accurate to within 0.3 unit.
i.e. margin of error <0.3
Std devition sample = 3.8
For 95% assuming sample size large we can use z critical value
Z critical = 1.96
we have
Sample size should be atleast 617 to get an accurate margin of error 0.3
Answer:
21
Step-by-step explanation:
21
Answer:
(7, 46)
Step-by-step explanation:
The offered answer choices have x-values of 7, 9, 10. The corresponding upper limit of y-value is ...
x=7 : y < 8·7 -3 = 53 . . . . . 46 is in the solution set, 60 is not
x=9 : y < 8·9 -3 = 69 . . . . 82 is not in the solution set
x=10 : y < 8·10 -3 = 77 . . . . 89 is not in the solution set
Of the choices offered, only (7, 46) is in the solution set.