Answer:
7.5 seconds.
Step-by-step explanation:
Substitute the distace 220m in the given equation:
d = 19t + t^2
200 = 19t + t^2
t^2 + 19t - 200 = 0
t = [-19 +/- sqrt(19^2 - 4*1*-200)] / 2
t = -19 +/- sqrt(1161) / 2
t = ( -19 +/- 34.07) / 2
t = 7.535 seconds
Answer:
Smallest number = 3500
Step-by-step explanation:
Rounding of numbers involve replacing numbers with simpler numbers. In order to round a number to the nearest thousand, the last 3 digits of the number should be considered. If the last 3 digits are less than 500, the number is rounded down(the thousand figure is unaffected), but if the last 3 digits are greater or equal to 500, the number is rounded up.
In this case, Yuri is thinking of a 4-digit whole number and he rounds his number to the nearest thousand. Since his answer is 4000, the smallest number yuri could be thinking of would be 3500 and the highest number he could be thinking of is 4499.
Thus, the smallest number Yuri could be thinking of is 3500
Answer : Direct Variation
Question :
Identify the variation as direct, inverse, joint or combined. A = 
We know direct variation is y = kx
Where k is the constant of proportionality
When value of x increases then y also increases. when x value decreases then y value decreases.
The value of y depends on value of x It means y is directly proportional to x.
Hence A =
is a direct variation.
Answer:
a) 0.997 is the probability that the breaking strength is at least 772 newtons.
b) 0.974 is the probability that this material has a breaking strength of at least 772 but not more than 820
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 800 newtons
Standard Deviation, σ = 10 newtons
We are given that the distribution of breaking strength is a bell shaped distribution that is a normal distribution.
Formula:
a) P( breaking strength of at least 772 newtons)
Calculation the value from standard normal z table, we have,

0.997 is the probability that the breaking strength is at least 772 newtons.
b) P( breaking strength of at least 772 but not more than 820)

0.974 is the probability that this material has a breaking strength of at least 772 but not more than 820.
Answer:
He pays to the cab driver for 25 miles.
Step-by-step explanation:
Consider the provided information.
Let us consider he walks x miles at the rate of 4 miles per hour.
As we know 
Therefore, time taken is: 
He get a taxi for (31-x) miles at the rate of 50 miles per hour.
Therefore, time taken is: 
It took 2 hours after he started.
That means the sum of time take is 2 hours.





Hence he walk 6 miles and he get a taxi for 31-6=25 miles.
He pays to the cab driver for 25 miles.