lisa sold 81 magazine subscriptions, which is 27% of her class fundraising goal. how many magazine subscriptions does her class
1 answer:
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Answer:
<em>Roberto's speed in still water is 6 miles/hour and the river speed is 2 miles/hour</em>
Step-by-step explanation:
<u>Relative Speed</u>
When a body is moving at a constant speed v, the distance traveled in a time t is:
When Roberto rows downstream, his speed in still water is added to the speed of the water, making it easier to travel the required distance.
When Roberto rows upstream, his speed in still water is affected by the speed of the water, both are subtracted and the required distance is covered in more time.
Let's call
x = Roberto's rowing speed in still water
y = Speed of the river current
The speed when rowing downstream is x+y, thus the distance traveled is
Where t1=2.5 hours. Substituting values:
Rearranging, we find the downstream equation:
The speed when rowing upstream is x-y, and the distance traveled is
Where t2=5 hours. Substituting values:
Rearranging, we find the upstream equation:
Multiplying [1] by 2:
Adding this equation to [2]:
Solving:
Dividing [2] by 5:
Solving for y
Thus, Roberto's speed in still water is 6 miles/hour and the river speed is 2 miles/hour
Answer:
b. The supplements of congruent angles are congruent
Explanation:
Note that
is a supplement of 
and 
is a supplement of 
.
Since
, 
because the supplement of the congruent angles are congruent.
b. The supplements of congruent angles are congruent
Explanation:
Note that
Since