Question 1075124
for simple interest,
{{{ I = P*r*t }}}
They are talking about annual interest, so
{{{ t = 1 }}}
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For account earning 7.6% interest:
{{{ I[1] = P*.076*1 }}}
{{{ I[1] = .076P }}}
For account earning 3.9% interest:
{{{ I[2] = 2P*.039*1 }}}
{{{ I[2] = .078P }}}
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{{{ I[1] + I[2] = 3080 }}}
{{{ I[1] + I[2] = .076P + .078P }}}
{{{ I[1] + I[2] = .154P }}}
{{{ .154P = 3080 }}}
{{{ P = 20000 }}}
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$20,000 was invested @ 7.6% interest
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check answer:
{{{ I[1] = .076P }}}
{{{ I[1] = .076*20000 }}}
{{{ I[1] = 1520 }}}
and
{{{ I[2] = .078P }}}
{{{ I[2] = .078*20000 }}}
{{{ I[2] = 1560 }}}
and
{{{ I[1] + I[2] = 1520 + 1560 }}}
{{{ I[1] + I[2] = 3080 }}}
OK