Answer:
<h2>3,600 m²</h2>
Step-by-step explanation:
The formula of a surface area of a sphere:

<em>R</em><em> - radius</em>
<em />
We have <em>R = 30m</em>.
Substitute:

Answer:
The population proportion is estimated to be with 99% confidence within the interval (0.1238, 0.2012).
Step-by-step explanation:
The formula for estimating the population proportion by a confidence interval is given by:

Where:
is the sample's proportion of success, which in this case is the people that regularly lie during surveys,
is the critical value needed to find the tails of distribution related to the confidence level,
is the sample's size.
<u>First</u> we compute the
value:

<u>Next</u> we find the z-score at any z-distribution table or app (in this case i've used StatKey):

Now we can replace in the formula with the obtained values to compute the confidence interval:

Answer:
Step-by-step explanation:
Let the speed of Masha = s, speed of Dasha = d
- Distance = 20 km
- Time difference = 20 min = 1/3 hr
- Speed difference = 2 km/h
<u>As per above info we get following equations:</u>
- s = d + 2
- 20/s + 1/3 = 20/d
<u>Substitute s and solve for d:</u>
<u>Get rid of fraction by multiplying all terms by 3d(d + 2):</u>
- 60d + d(d + 2) = 60(d + 2)
- 60d + d² + 2d = 60d + 120
- d² + 2d = 120
- d² + 2d + 1 = 121
- (d + 1)² = 11²
- d + 1 = 11
- d = 10
<u>Find s:</u>
<u>The answer is</u>
- Masha's speed 12 km/h and Dasha's speed 10 km/h
Answer:
80 km/hr
Step-by-step explanation:
This is asking for speed.
Speed=Distance/Time
Speed=720/9
Speed=80 km/hr
Answer:
13
Step-by-step explanation:
divide 150 by 12
the answer is 12.5
round 12.5
;)