Question 170451
Let {{{x}}} ---> money inv. 7%
Therefore, {{{2x+2000}}} ---> money inv. @ 11%
It follows,
{{{0.07x+(2x+2000)0.11=3990}}}
{{{0.07x+0.22x+220=3990}}}
{{{0.29x=3990-220=3770}}}
{{{cross(0.290)x/cross(0.29)=cross(3770)13000/cross(0.29)}}}
{{{x}}}=$13,000, amount inv @ 7%
Then,
{{{2*13000+2000=26000+2000}}}=$28,000, amount inv at 11% (ANSWER)
Check,
{{{0.07*13000+28000(0.11)=3990}}}
{{{910+3080=3990}}}
{{{3990=3990}}}
Thank you,
Jojo