$8,000 is invested in two different accounts earning 3% and 4% interest. If the two accounts earn a total of $295 in interest, how much money was invested at 3%?
A $2,500
B $3,500
C $5,500

Question

$8,000 is invested in two different accounts earning 3% and 4% interest. If the two accounts earn a total of $295 in interest, how much money was invested at 3%? 
A $2,500
B $3,500
C $5,500

anonymous · Answer

@amandaemiko Let A be the amount invested at 3%, B the amount at 4%.
Total value: A+B=8000
Interest: Multiply eq. 1 by -3 and add to eq. 2,
- 3A - 3B + 3A + 4B = -24000 + 29500
B=5500
Then from eq. 1,
A + 5500 = 8000
A = 2500

so A is the answer