After 2 hours she wrote 3 entries.
after 4 hours she wrote 6 entries.
This means that for same period she is writing same number of entries which means her "writing speed" is constant.
that means that graph is linear function (straight line).
slope we calculate by putting coordinates of y and x of any dot on that line. we can use one of those given by text of task. (in 2 hours she wrote 3 entries)
y = k*x
k = y/x
k = 1.5
Answer:
1/8
Step-by-step explanation:
sin²(π/8) − cos⁴(3π/8)
Use power reduction formulas:
1/2 (1 − cos(2×π/8)) − 1/8 (3 + 4 cos(2×3π/8) + cos(4×3π/8))
Simplify:
1/2 (1 − cos(π/4)) − 1/8 (3 + 4 cos(3π/4) + cos(3π/2))
1/2 (1 − √2/2) − 1/8 (3 + 4 (-√2/2) + 0)
1/2 − √2/4 − 1/8 (3 − 2√2)
1/2 − √2/4 − 3/8 +√2/4
1/2 − 3/8
1/8
Given:
population mean, μ =135
population standard deviation, σ = 15
sample size, n = 19
Assume a large population, say > 100,
we can reasonably assume a normal distribution, and a relatively small sample.
The use of the generally simpler formula is justified.
Estimate of sample mean
Estimate of sample standard deviation
to 5 decimal places.
Thus, using the normal probability table,
Therefore
The probability that the mean weight is between 125 and 130 lbs
P(125<X<130)=0.0731166-0.0018308
=
0.0712858
Answer: you're right, it is D.
Step-by-step explanation:
Step-by-step explanation:
Let the original speed of the train be x km/h.
Time taken to cover a distance of 360 km = 360/x hours.
New speed of the train = (x+5) km/h.
Time taken to cover a distance of 360 km at new speed = 360/x+5 hours.
Since, the train takes 1 hour less time,
∴360/x - 360/ x+5 = 1
⇒360 (5) = x² + 5x
⇒1800 = x² + 5x
⇒x² + 5x - 1800 = 0
⇒x² + 45x - 40x - 1800 = 0
⇒x (x+45) - 40( x +45) = 0
⇒(x+45) (x-40) = 0
⇒x = (-45), 40
But since speed cannot be in negative.
∴x = 40 km/hr.
Hence, the original speed of the train is 40 km/h.
