Question 200700
 Donna invested her $33,000 bonus and received a total of $970 in interest
 after one year. If part of the money returned 4% and the reminder 2.25% then
 how much did she invest at each rate?
:
Let x amt invested at 4%
then
(33000-x) = amt invested at 2.25%
:
Write an equation using the decimal values for the rates:
.04x + .0225(33000-x) = 970
:
.04x + 742.5 - .0225x = 970
:
.04x - .0225x = 970 - 742.5
:
.0175x = 227.5
x = {{{227.5/.0175}}}
x = $13,000 invested at 4%
then
33000 - 13000 = $20,000 invested at 2.25%
:
Check solution;
.04(13000) + .0225(20000) = 
520 + 450 =970
:
:
100.)Ticket of Sales. Tickets for a concert were sold to adults for $3.00
 and to students for $2.00. If the total receipts were $824.00 and twice as
 many adult tickets were sold, then how many of each were sold?
:
3a + 2s = 824
:
"twice as many adult tickets were sold,"
a = 2s
:
Replace a with 2s in the 1st equation, find s
3(2s) + 2s = 824
6s + 2s = 824
8s = 824
s = {{{824/8}}}
s = 103 students
:
You can find the no. of adults