<PRE><B>Question 1161940</B>
let p = original amt invested
let r = original rate of interest in decimal form
:
Angel gets $48 a year for an investment.
r*p = 48
r = {{{48/p}}}
 If Angel had invested $300 more and the interest was 0.5% less, Angel would receive $52.50.
(r-.005)(p+300) = 52.50
FOIL
rp + 300r - .005p - 1.5 = 52.50
rp + 300r - .005p - 1.5 - 52.50 = 0
rp + 300r - .005p - 54 = 0
we know rp = 48, therefore
48 + 300r - .005p - 54 = 0
300r - .005p - 6 = 0
replace r with 48/p
300(48/p) - .005p - 6 = 0
14440/p - .005p - 6 = 0
Multiply by p
14440 - .005p^2 - 6p = 0
a quadratic equation
-.005p^2 - 6p + 14440 = 0
Using the quadratic formula, my positive solution
1202.22  ~ $1200 invested
then using some decent values
r = 48/1200
r = .04 or 4% interest
 How much did Angel invest and at what interest? $1200, 4% 
;
:
see if this works when r = 3.5 and p = 1500
.035 * 1500 = 52.50 </PRE>