Tori invested $8000 in money market funds. Part was invested at 5% simple interest, and the rest was invested at 7% simple interest. At the end of 1 year, tori had earned $496 in interest. How much did she invest in each fund?

let investment in 5% =  $x

investment in 7% = $(8000-x)

interest = 5x/100 + 7(8000-x)/100

=> -2x/100 + 560 = 496

=> 2x/100 = 64

=> x = 3200

invest in 5% = $3200

invest in 7% = $4800