Question 163855
63) x = amount invested
They invested a total of $16000 but we do not know how much in each account. Most likely they invested the larger amount in the 8% interest. So we will make x times 8%;
.08x; the amount invested at 8%
The remainder was invested at 4.5%, so we need to subtract that from $16000;
.045(16000-x)
They earned a total of $1070, so we add the two amounts together to equal 1070;
.08x + .045(16000-x)=1070
Now we solve for x;
.08x + 720 - .045x = 1070
collect like terms;
.035x+720=1070
Subtract 720 from both sides;
.035x=350
divide .035 to both sides;
x=10000
Now this is the amount at 8% in the corporate bond, so we subtract that from the 16000 - 10000 = $6000
61)We do not know how much interest was earned, but we do know that they are equal. So we will make these two equal to each other;
.045x = .035(42000-x)
.045x = 1470-.035x
.045x+.035x=1470
.08x=1470
x=$18375 - this would be the amount at 4.5%
42000-18375 = $23625  - amount at 3.5%
Hope you understand, let me know if you do not.
:)