Question

Mingfa says, "My sister and I have $130 altogether. If my mother gives me another

$10, I'll have 3 times as much money as my sister."
How much money does Mingfa actually have?​

Answer 1

Given:

Total amount of Mingfa and her sister = $130

If Mingfa amount increased by $10, then the new amount is equal to three times of as much money as her sister.

To find:

How much money does Mingfa actually have?​

Solution:

Let, Mingfa have $x and her sister has $y initially. Then,

`x+y=130` ...(i)

If Mingfa amount increased by $10, then the new amount is equal to three times of as much money as her sister.

`x+10=3y` ...(ii)

Substitute the value of x from (ii) in (i).

`(3y-10)+y=130`

`4y=130+10`

`4y=140`

Divide both sides by 4.

`y=35`

Putting
`y=35` in (i), we get

`x+35=130`

`x=130-35`

`x=95`

Therefore, Mingfa have $95.