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3 years ago

A car travels 45km in an hour. In each of the next two hours, it travels 78km. What is the average speed of the car.

Mathematics

1 answer:

romanna [79]3 years ago

7 0

Answer:

The average speed of car is 67 kilometers per hour.

Step-by-step explanation:

Given that:

Distance travelled in one hour = 45 km

Distance travelled in next 2 hours = 78*2 = 156 km

Total distance = 45+156 = 201

Total time = 1+2 = 3 hours

Average speed of the car = $\frac{Total\ distance}{Total\ time}$

Average speed of the car = $\frac{201}{3}$

Average speed of the car = 67 km/hr

Hence,

The average speed of car is 67 kilometers per hour.

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Subtract 6 from me. Then multiply by 2. If you subtract 40 and then divide by 4, you get 8. What number am I?

aliina [53]

Answer:

Step-by-step explanation:

Let the number be "x"

We translate the word equation to algebraic equation.

First,

subtract 6 from me, so we have:

x - 6

Now,

Multiply by 2, so we have:

2(x-6)

Now,

Subtract 40, then divide by 4:

$\frac{2(x-6)-40}{4}$

Now, you get "8", so equate this to 8, we get:

$\frac{2(x-6)-40}{4}=8$

We now solve using algebra:

$\frac{2(x-6)-40}{4}=8\\2(x-6)-40=4*8\\2(x-6)-40=32\\2x-12-40=32\\2x-52=32\\2x=32+52\\2x=84\\x=42$

The number is 42

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How to reduce fractions

bulgar [2K]

Answer:

To simply or reduce fraction by dividing both the numerator and denominator by a number they are both divisible by.

Example:

3/12 both numbers are divisible by 3 do divide it and it becomes 1/4

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A bus on a regular schedule takes 3 1/4 hours to reach its destination. The express bus takes 2 1/2 hours to make the same trip.

alisha [4.7K]

To find this answer, we should subtract 2 1/2 from 3 1/4. The simplest way to do this is to turn them into improper fractions, found the least common denominator, and subtract the numerators.

3 1/4=13/4
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The least common multiple is 4, so we should multiply the numerator and denominator of 5/2 by 2.

5/2=10/4

Now we can just subtract the numerators.

13/4-10/4=3/4

Using the math above, we can see that it saves D. 3/4 hours.

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A person jogged 10 times along the perimeter of a rectangular field at the rate of 12 kilometers per hour for 30 minutes. If the

notsponge [240]

Answer:

The area of the rectangular field is 20,000 square meters.

Step-by-step explanation:

1. Let's review the information given to us to answer the question correctly:

Number of times a person jogged along the rectangular field = 10

Speed of the person jogging = 12 km per hour

Time he/she jogged = 30 minutes = 0.5 hours

Length of the field = twice its width

2. Find the area of the field in square meters.

Step A: Let's calculate the distance the person jogged

Let's recall the formula of the speed:

Speed = Distance/Time

Distance = Speed * Time

Replacing with the values we know:

Distance = 12 * 0.5

Distance = 6 kilometers

Step B: Let's calculate the perimeter of the rectangular field

Distance jogged = ¨Perimeter * 10

6 kilometers = Perimeter * 10

Perimeter = 6/10

Perimeter = 0.6 kilometers = 0.6 * 1,000 = 600 meters

Perimeter = 2 * Length + 2 * Width

x = Width of the rectangular field

2x = Length of the rectangular field

600 = 2 * 2x + 2 * x

600 = 4x + 2x

600 = 6x

x = 600/6 = 100 meters ⇒ 2x = 200 meters

Step C: Let's calculate the area of the rectangular field

Let's recall the formula of the area of a rectangle:

A = Length * Width

A = 200 * 100

A = 20,000 m² (square meters)

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3 years ago