Question 150683
Let {{{a}}}= the 8% per yr investment
Let {{{b}}}= the 10% per year investment
{{{.08a + .1b = 940}}}
{{{a + b = 10000}}}
{{{b = 10000 - a}}}
{{{.08a + .1*(10000 - a) = 940}}}
{{{.08a + 1000 - .1a = 940}}}
{{{-.02a = -60}}}
{{{a = 60/.02}}}
{{{a = 3000}}}
And, since
{{{a + b = 10000}}},
{{{3000 + b = 10000}}}
{{{b = 7000}}}
He invested $3,000 in the 8% investment
He invested $7,000 in the 10% investment
check:
{{{.08a + .1b = 940}}}
{{{.08*3000 + .1*7000 = 940}}}
{{{240 + 700 = 940}}}
{{{940 = 940}}}
OK