1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Ronch [10]
3 years ago
15

John is twice as old as Mary. The sum of thelr ages is 21. How old Is Mary?

Mathematics
2 answers:
Cerrena [4.2K]3 years ago
7 0

Answer:

Step-by-step explanation:

Let Mary's age = x years

John's age = 2 * x = 2x

The sum of their ages = 21

x + 2x = 21

3x = 21

Divide both sides by 3

x = 21/3

x = 7

Mary's age = 7 years

Kaylis [27]3 years ago
5 0

Answer:   7 years

Step-by-step explanation:

let x be the age of Mary

so John's age will be 2x

the equation becomes

2x+x=21

3x=21

x=21/3

x=7

You might be interested in
The shape below is a composite figure made up of two rectangular prisms, what is the volume of the figure?
gregori [183]

Answer:

<u>11098 cm³</u>

Step-by-step explanation:

<u>Volume of top prism</u>

  • V = 62 x 3 x (13 - 7)
  • V = 186 x 6
  • V = 1116 cm³

<u>Volume of bottom prism</u>

  • V = 62 x 23 x 7
  • V = 1426 x 7
  • V = 9982 cm³

⇒ Total volume = Volume (top) + Volume (bottom)

⇒ Total volume = 1116 + 9982

⇒ Total volume = <u>11098 cm³</u>

5 0
2 years ago
Read 2 more answers
A triangle has side lengths of
Angelina_Jolie [31]

Answer:

3 is the right one

Step-by-step explanation:

Simple math you know

3 0
3 years ago
1.Anthony has decided to purchase a $19,000 car. He plans to put 20% down toward the purchase and to finance the rest at a 6.8%
Nikitich [7]
<h2>First step/Equation</h2>

Answer:

 $362.57

Step-by-step explanation:

A suitable calculator or finance app can find the monthly payment for you. This result comes from a TI-84 calculator.

___

The second attachment shows the parameters of the payment function. With 20% down, Anthony is only financing 80% of the price of his car. Of course, there are 12 months in a year, so 4 years worth of payments will be 48 payments. The calculator uses negative values for amounts you pay.

___

No doubt your reference material shows you a formula for computing loan payments. One such is ...

 A = Pr/(1 -(1+r)^-n)

where r is the monthly interest rate, 0.068/12, and n is the number of payments, 48. The principal amount of the loan, P, will be 19,000×0.80. This formula gives the same result as that shown above and below

3 0
3 years ago
What is Y-3x=-2 and Y+x=-6
love history [14]
Rearranging the first equation gives:

y=3x-2

Substituting this into the other equation gives:

y+x=-6&#10;\\(3x-2)+x=-6&#10;\\4x-2=-6&#10;\\4x=-4 \\x=-1

If x=-1:

y+(-1)=-6&#10;\\y=-5

So x=-1, y=-5
5 0
3 years ago
Read 2 more answers
Karl uses 8 whole square tiles and 8 half square tiles to make a mosaic. What is the area of his mosaic?​
trapecia [35]

Answer:

48

Step-by-step explanation:

8 squares=32

8 half squares=16

32+16=48

There are 4 sides to a 8 whole squares 8*4=32

There a 2 sides to 8 half squares 8*2=16

8 0
3 years ago
Other questions:
  • THE RIGHT ANSWER WILL RECIEVE A BRAINLEST AND POINTS AND THANXS!!!
    10·1 answer
  • 0.9(x-20)=830 solve the equation
    6·1 answer
  • What is the equation of the line that is parallel to the line y − 1 = 4(x + 3) and passes through the point (4, 32)?
    5·1 answer
  • Triangle abc is a right triangle if side ac=7 and bc=10 whats the measure of side ab
    14·1 answer
  • A prism with a base area of 3 m² and a height of 4 m is dilated by a factor of 3/2 . What is the volume of the dilated prism?
    14·2 answers
  • What is the difference in the measures of the radii of cylinder Y and cylinder Z, in inches?
    14·2 answers
  • Mr.Roshan will buy 12 1/2 pounds Beef for a cookout.The price for the first 3 pounds of beef is $4.99 per pound. After that,The
    13·1 answer
  • Two Florida panthers were weighed. One weighs 6x + 21 pounds and the two together weigh 14x + 11 pounds. How much does the other
    11·2 answers
  • 1<br> 15<br> 3x =<br> 2<br> Circle the ratio<br> xiy<br> 6:1<br> 1:6<br> 3:2<br> 2:3
    12·1 answer
  • 7 squared minus y equals 6 then y equals
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!