7x-x ............................ .

The cone and cylinder below have equal surface area

Elza [17]

I think the answer is true.

3 0

3 years ago

40% of the students passed both exams. 80% of the students passed the second exam. how many students (in percent) who passed the

navik [9.2K]

50%. students (in percent) who passed the second exam also passed the first exam.

Let's imagine that there are 100 kids in the teacher's class. We know that 40 of them passed BOTH tests, and 80 passed the second test.

Because if they weren't, they wouldn't have passed the first test and consequently wouldn't have passed both, we can be sure that the group of students who passed BOTH tests is only made up of the 80 who passed the second test.

Thus, both tests were passed by 40 of the 80 pupils who passed the second one:

40/80 = 1/2 = 50%.

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7 0

1 year ago

For the following problem:

Gnoma [55]

(a) identify the unknown quantities and introduce variables to represent them

Answer:

Distance traveled by Amelia upstream is 12 km. Let us call it x.

So that x = 12 km

Distance traveled downstream is unknown. But by reading and understanding the question, one can tell that the distance covered on trip downstream must be the same as distance traveled while going upstream.

Let us call it y.

So that y = x = 12 km

y = 12 km

Speed of Amelia while swimming = s

Speed of the current in the river = c

(b) write equations which express the information given in the statement of the problem

Answer:

s - c = 2 ------eq-1

s + c = 6 ------eq-2

Step-by-step explanation:

Speed of Amelia's swimming is same then why is the time taken while going upstream different than while going downstream?

It is because the resistance of current in the river is in the downward direction. It explains why Amelia takes more time to go upstairs and much less to come back.

Using Speed = Distance traveled/Time

While going upstream:

Amelia is going against the current, hence the direction for Amelia and river's current is opposite. We get the equation:

s - c = 12/6 = 2------eq-1 where t = 6 hours

While going downstream:

Amelia is going with the current, hence the direction for Amelia and river's current is same. We get the equation:

s + c = 12/2 = 6------eq-2 where t = 2 hours

(c) solve the equations and give the answer

Answer:

speed of the current in the river = c = 4 km/h

Step-by-step explanation:

To find = c?