Person X invested $10,000 in three accounts.
. . Account A pays 4.5% interest.
. . Account B pays 6.2% interest.
. . Account C pays 3.5% interest.
X decides to invest into account B double the sum of the other two accounts.
When the first dividends came, they earned $549 interest.
How much invested into each account?
If we organize the information, everything is clearer . . .
In the second column, we have: .
In the last column: .
Multiply by 1000: .
Solve the system of equations: .
And we get: . in account
Substitute into : . in account
Then: . in account