let x = the amount invested at 11%, and (x - 1400) = amount invested at 7%
0.11x + [0.07(x - 1400)] = 820
0.11x + 0.07x - 98 = 820
0.18x = 918
x = 918 / 0.18
x = $5,100
(x - 1400) = $3,700
check math:
5100 * 0.11 = 561
3700 * 0.07 = 259
sum: $820
X * 0.07 + (x+1400) * 0.11 = 820 solve for X
Eva invested a certain amount of money at 7% interest and $1400 more than that amount at 11%. Her total yearly interest was $820. How much did she invest at each rate?
