The 63 is the err in her explanation here.
The Given equation is , 3 x + x = 440,
Let speed of train A is x Km/hour and Speed of train B which is a Bullet train which starts from same station but from different platform is 3 times the speed of train A.
And Sum of their Velocities is i.e Velocity of train A and Velocity of train B is 440 Km/hour.
Answer:
50° and 130°
Step-by-step explanation:
∠1 is a chord- chord angles and is calculated as
∠1 = 0.5( arc RQ + arc ST) = 0.5(53 + 47)° = 50°
∠1 and ∠2 form a straight angle and are supplementary, hence
∠2 = 180° - 50° = 130°
Answer:
Step-by-step explanation:
Hello!
The objective is to estimate the average time a student studies per week.
A sample of 8 students was taken and the time they spent studying in one week was recorded.
4.4, 5.2, 6.4, 6.8, 7.1, 7.3, 8.3, 8.4
n= 8
X[bar]= ∑X/n= 53.9/8= 6.7375 ≅ 6.74
S²= 1/(n-1)*[∑X²-(∑X)²/n]= 1/7*[376.75-(53.9²)/8]= 1.94
S= 1.39
Assuming that the variable "weekly time a student spends studying" has a normal distribution, since the sample is small, the statistic to use to perform the estimation is the student's t, the formula for the interval is:
X[bar] ±
* (S/√n)

6.74 ± 2.365 * (1.36/√8)
[5.6;7.88]
Using a confidence level of 95% you'd expect that the average time a student spends studying per week is contained by the interval [5.6;7.88]
I hope this helps!
Answer:
x=-3
Step-by-step explanation: