Suppose part of 17000 is to be invested at 10 and the remain

Suppose part of $17,000 is to be invested at 10% and the remainder at 8%. How much should be invested at each rate in order to earn an annual income of $1592. (Section 1.2)

Solution

Let $x be invested at 10%

So, interset in 1 year = x*0.1*1 = 0.1x

Remaining 17000 -x is invested at 8%

So, interset in 1 year = (17000 -x)0.08*1 = 1360 -0.08x

So, 0.1x +1360 -0.08x = 1592

0.02x = 232

x= $11600 at 10 % and 17000 - 11600 = $5400 is invested at 8%