Question

Tara, Jennifer, and Mindy donated some money to a charity. Jennifer donated twice as much as Tara, and Mindy donated $10 less than Jennifer. If the total amount donated to the charity is $50, then how much money did Tara donate?

Answer 1

`$12`

Explanation:

Let's say that Tara donated `t` dollars, Jennifer donated `j` dollars, and Mindy donated `m` dollars.

• Jennifer donated twice as much as Tara `-> j = 2t`
• Mindy donated `$10` less than Jennifer `-> m = j - 10`
• The total amount donated is `$50` `-> j + m + t = 50`

We already have `j` in terms of `t`, so we should find `m` in terms of `t`. To do this, substitute `j=2t` into the second equation.

`m = 2t - 10`

Now we can substitute the equations `j=2t` and `m=2t-10` into the third equation and solve for `t`.

`j + m + t = 50`
`2t + 2t-10 + t = 50`
`5t - 10 = 50`
`5t = 60`
`t=12`

Tara donated `$12`.