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Which answer correctly estimates the quotient of 102.02 ÷ 4.011?

BigorU [14]

Well the answer is A) about 25

3 0

3 years ago

It takes a train 60 seconds to completely drive through a bridge of 1260 m, and 90 seconds to completely drive through a tunnel

Olegator [25]

The length of train is 120 meters

The speed of train is 25 meter per second

Solution:

The speed is given by formula:

$speed = \frac{distance}{time}$

Given that,

It takes a train 60 seconds to completely drive through a bridge of 1260 m

And 90 seconds to completely drive through a tunnel of 2010 m

Let the length of the train be "x"

The total distance travelled by the train across the bridge is given by:

total distance = x + 1260 + x = 2x + 1260

[ here we use x + x to represent that train completely drives through bridge ]

The time taken is given as 60 seconds

Therefore, the speed is given as:

$speed = \frac{2x+ 1260}{60}$

The total distance travelled by the train through the tunnel is given by:

total distance = x + 2010 + x = 2x + 2010

The time taken is given as 90 seconds

Therefore, the speed is given as:

$speed = \frac{2x+ 2010}{90}$

The speed of the train was the same in both cases.

Equate both speeds

$\frac{2x+ 1260}{60} = \frac{2x+ 2010}{90}$

$\frac{x+630}{30} = \frac{x+1005}{45}$

$45(x+630) = 30(x+1005)\\\\45x + 28350 = 30x + 30150\\\\45x - 30x = 30150 - 28350\\\\15x = 1800\\\\x = 120$

Thus length of train is 120 meters

Find the speed of train:

$speed = \frac{2x+ 1260}{60}\\\\speed = \frac{2(120) + 1260)}{60}\\\\speed = 25$

Thus speed of train is 25 meter per second

5 0

3 years ago

Evaluate f(x)=2x-5 for x=3

Fiesta28 [93]

F(x)=2(3)-5
f(x)=6-5
f(x)=1

3 0

4 years ago

all unicorns on rainbow island are either green or yellow. every time the clock strikes midnight the unicorns change their color

Oksi-84 [34.3K]

77 unicorns, because yesterday the ratio was 6:5 and today it is 3:4. If you add the numbers for both ratios together, you get 11 and 7. Finding the LCM of these two gives 77 (because 7 and 11 are both prime).

You find the LCM of the sums because when you find values based on ratios, you divide value by the sum of the ratio.

e.g. I have 100 fruits. The ratio of apples to oranges is 2:3. How many apples are there?

To solve this you'd add 2 and 3 (5), divide 100 by 5 (20), multiply that by 2 (40) because that's the ratio of apples to oranges.

In this case, you do the reverse. So If I have 77 unicorns, then yesterday there were (77/11 = 7, 7*6= 42, 7*5= 35) 42 green unicorns and 35 yellow. The sum of 42 and 35 is 77. If you do this process with the other ratio you'll get similar results as well.

6 0

3 years ago

A soccer team wins 65% of its matches, and 15% of its matches end in a draw. If the team is scheduled to play 20 matches, about

Finger [1]

The team plays 20 matches.

65% of the matches, the teams wins
= 20 * 0.65
= 13 matches

15% of the matches, the games ends in draw.
= 20 * 0.15
= 3 matches

The team is expected to lose in
= 20 - 13 - 3
= 4 matches

3 0

3 years ago