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2 years ago

Three years ago Tom was twice as old as Jean, and in two years the sum of their ages will be 28 years. Find their present ages.

Mathematics

2 answers:

natali 33 [55]2 years ago

4 0

Answer:

Tom is 15 years old and Jean is 9 years old

Step-by-step explanation:

Let call:

x: the age of Tom

y: the age of Jean

From the sentence: three years ago Tom was twice as old as Jean, we get the first equation:

(x-3)=2(y-3)

Solving for x:

x=2y-6+3

x=2y-3

From the sentence: in two years the sum of their ages will be 28 years, we get the second equation:

(x+2)+(y+2)=28

Solving:

x+y+4=28

x+y=28-4

x+y=24

Now, we have two equations with two incognites:

equation 1: x=2y-3

equation 2: x+y=24

For finding the values of x and y we need to replace the x = 2y-3 on the second equation and solve for y, as following:

(2y-3)+y=24

2y+y-3=24

3y=27

y=27/3

y=9

Then, we Replace y=9 on the first equation and get:

x=2(9)-3

x=18-3

x=15

Now, we have the values of x and y that satisfy the two formulate equation, so the answer is x equal to 15 and y equal to 9. So, Tom is 15 years old and Jean is 9 years old

lubasha [3.4K]2 years ago

3 0

Answer:

Jean is 9 and Tom is 15.

Step-by-step explanation:

3 years ago, Tom was 12 and Jean was 6, hence Tom was twice as old as Jean.

Since that was their age 3 years ago, they are currently 15 (Tom) and 9 (Jean).

Add 2 years to each of these ages, you get 17 and 11.

17 + 11 = 28

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13 over 15 divided by 7 over 10 in simplest form

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If you would like to write (13/15) / (7/10) in the simplest form, you can calculate this using the following steps:

(13/15) / (7/10) = <span>(13/15) * (10/7) = (13 * 2) / (3 * 7) = 26/21 = 1 5/21
</span>
The correct result would be <span>26/21.</span>

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2 years ago

For which function does f decrease by 15% every time x increases by 1

LenaWriter [7]

Answer:

$f(x) = 0.85^{x}$

Step-by-step explanation:

The exponential function that decrease by 15% every time x increases by 1 is given by:

$f(x) = {(1 - 0.15)}^{x}$

We simplify the parenthesis to get:

$f(x) = 0.85^{x}$

Therefore the decrease by 15% every time x increases by 1 is

$f(x) = {0.85}^{x}$

The second choice is correct.

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2 years ago

Elena bikes 20 minutes each day for exercise. Write an equation to describe the relationship between her distance in miles, D, a

ValentinkaMS [17]

Answer:

The equation to describe the relationship between Elena distance:

a) D = 4.34 miles, b) D = 4.25 miles and c) 12D = M + 3N miles.

Solution:

Given, Elena bikes 20 minutes each day for exercise.

We have to write an equation to describe the relationship between her distance in miles, D, and her biking speed, in miles per hour,

We know that, distance travelled = speed time

a. At a constant speed of 13 miles per hour for the entire 20 minutes

Her speed is 13 miles per hour.

Then, distance D miles = 13 miles per hour 20 minutes

b. At a constant speed of 15 minutes per hour for the first 5 minutes, then at 12 miles per hour for the last 15 minutes

Now, total distance travelled = distance travelled with 15 mph + distance travelled with 12 mph

c. At a constant speed of M miles per hour for the first 5 minutes, then at N miles per hour for the last 15 minutes

Now, total distance travelled = distance travelled with M mph + distance travelled with N mph

Hence, a) D = 4.34 miles, b) D = 4.25 miles and c) 12D = M + 3N miles.

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2 years ago

a school baseball team raised $810 for new uniforms. each player on the team sold one book of tickets. There were 10 tickers in

Orlov [11]

1 Book = $30
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27 books

4 0

2 years ago

Read 2 more answers

The cost of taking your pet aboard the air flight with you in the continental US varies according to the airlines. The five numb

melisa1 [442]

Answer: The lowest value: 100 and highest value: - 150 .

If we were to build the box plot for this data, the box would stretch between $Q_1= 100$ and $Q_3= 125$ .

Step-by-step explanation:

We know that the box-plot is the graphical way to represent the five -number summary (Minimum value , First quartile $(Q_1)$ , Median , Third Quartile $(Q_3)$ , Maximum value).

Where , the box streches between the first quartile $(Q_1)$ and the third quartile $(Q_3)$ .

Given : The cost of taking your pet aboard the air flight with you in the continental US varies according to the airlines.

The five number summary for prices based on a sample of major US airlines was:

Min = 60,

$Q_1= 100$

Median = 110

$Q_3= 125$

Max = 150

If we were to build the box plot for this data, the box would stretch between $Q_1= 100$ and $Q_3= 125$ .

Hence, the lowest value: 100 and highest value: 125 .

8 0

2 years ago