Answer:
1.778 times more or 16/9 times more
Step-by-step explanation:
Given:
- Mirror 1: D_1 = 8''
- Mirror 2: D_2 = 6"
Find:
Compare the light gathering power of an 8" primary mirror with a 6" primary mirror. The 8" mirror has how much light gathering power?
Solution:
- The light gathering power of a mirror (LGP) is proportional to the Area of the objects:
LGP ∝ A
- Whereas, Area is proportional to the squared of the diameter i.e an area of a circle:
A ∝ D^2
- Hence, LGP ∝ D^2
- Now compare the two diameters given:
LGP_1 ∝ (D_1)^2
LGP ∝ (D_2)^2
- Take a ratio of both:
LGP_1/LGP_2 ∝ (D_1)^2 / (D_2)^2
- Plug in the values:
LGP_1/LGP_2 ∝ (8)^2 / (6)^2
- Compute: LGP_1/LGP_2 ∝ 16/9 ≅ 1.778 times more
Answer:
599/711
Step-by-step explanation:
Band Sports Debate Total
Male 105 320 7 432
Female 105 160 14 279
Total 210 480 21 711
P(female or plays sports)
We want the probability that they are female or play sports, but we cannot double count the female sports players, so we subtract them
P(female) + P (sports) - (female and sports)
female/total + sports/total - female sports/ total
279/711 + 480/711 - 160/711
599/711
If the current in a stream moves at a rate of 7 mph. If a boat travels 98 miles downstream in the same time that it takes to travel 49 miles upstream then the speed of the boat in still water is 21 miles per hour.
<h3>What is speed?</h3>
Speed is the distance covered by an object in a certain time period. It is also known as velocity. The formula of speed is as follows:
Speed=Distance/ Time.
<h3>How to calculate speed?</h3>
We have been given that the speed of stream is 7miles per hour.
Let v be the speed of the boat, and t the time to travel
98=t*(7+v) (1)
49=t(v-7) (2)
(1)+(2) => 2tv=147
7t+(49+7t)=98
14t+49=98
14t=49
t=49/14
t=7/2
Put the value of t in equation 1 to get the value of v:
98=t(7+v)
98=7/2(7+v)
196/7=7+v
28=7+v
v=28-7
v=21
Hence if the current in a stream moves at a rate of 7 mph. If a boat travels 98 miles downstream in the same time that it takes to travel 49 miles upstream then the speed of the boat in still water is 21 miles per hour.
Learn more about speed at brainly.com/question/4931057
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<h3>
Answer: D) One solution</h3>
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Work Shown:
2(b+3)-17 = 3b-7+b
2b+6-17 = 4b-7
2b-11 = 4b-7
-11+7 = 4b-2b
-4 = 2b
2b = -4
b = -4/2
b = -2
There is one solution and it is b = -2
A quick way to tell we have one solution is to note that both sides are a linear expression, and that the slopes of each linear expression are different values. If you had two lines with the same slope, then you'd have either parallel lines or coinciding lines (leading to no solutions and infinitely many solutions respectively). When you have two lines with two different slopes, then they are guaranteed to intersect only once. That intersection point is the solution.
