Answer:
300
Explanation:
Let x = cost of desktop computer; then x - 250 = cost of laptop computer
converting % to decimals, 9% = 0.09 and 6% = 0.06
Then, 0.09x + (x - 250)0.06 = $300
0.09x + 0.06x - 15 = $300
0.15x = $315
x = $2100
then x - 250 = $1850
Proof: $2100•0.09 + 1850•0.06 = $189 + $111 = $300