Mike is three times as old as his little sister, Mary. In 4 years, he will be twice as old as Mary. How old is Mary?

Question

15-07-2014
Mathematics

contestada

Mike is three times as old as his little sister, Mary. In 4 years, he will be twice as old as Mary. How old is Mary?

Respuesta :

Otras preguntas

after school a bus travels 1 block east 3 blovks south 2 blicks east 7 blocks north and 3 blocks west. Where is the bus compared to the school

which is greater 8/36 or 5/8

Mr Sudimack earned a 4% commission on the sale of a hot tub that cost $3755. How much did he earn?

what is a benefit of making a grocery list before buying food? you can figure out what you do and don't have in the house. you can check to see if you have any

you set up a plan to try to make yourself healthier. To become socially healthier you seek out friendships that are

what was the rule of law in roman justice

1.7 yard long and 14/5 yard long which one longer

Arrange these units from smallest to largest: decimeter meter kilometer millimeter centimeter nanometer and micrometer

rocks crack and shift when ? from moving plates become to great

Ryan2 Ryan2 · Answer 1 · 2014-07-15T23:22:23+02:00

Ryan2 Ryan2

15-07-2014

Mary: x yrs old
Mike: 3x yrs old

In four yrs:

Mary: x+4 yrs old
Mike: 3x+4 yrs old

As the text of task:

3x+4=2(x+4)
3x+4=2x+8
3x-2x=8-4
x=4

Mary is 4 yrs old

Answer Link

mariamikayla mariamikayla · Answer 2 · 2014-07-15T23:25:12+02:00

mariamikayla mariamikayla

15-07-2014

x-the age of Mike
y-the age of his sister

x=3y

x+4=2(y+4)
3y+4=2y+8
3y-2y=8-4
y=4 years

x=3*4=12 years

Answer Link