+422 If I put $500 into an account and left it alone for three years earning simple interest, and at the end of three years I withdrew $650, what interest rate was I earning? Can you explain how you got your answer so i can understand what to do.
$650 - $500 =$150 simple interest earned over 3 years.
$150 / 3 =$50 simple interest earned in 1 year.
$50 / $500 = 10 % simple interest rate per year.
+128474 Interst amount earned must have been 650 - 500 = $150
And I = Prt
Where I = interest P = original amount r =interest rate t = time in years
So
150 = 500 * r * (3)
150 = 1500 * r divide both sides by 1500
150 /1500 = 1/10 = r = .10 = 10% = interest rate
This makes sense.....the interst earned each year = .10 * 500 = $50
So...at the end of 3 years....we have 3 * 50 = $150 more than what we originally deposited
+1486 If I put $500 into an account and left it alone for three years earning simple interest, and at the end of three years I withdrew $650, what interest rate was I earning? Can you explain how you got your answer so i can understand what to do.
Simple interest formula is: A = P ( 1 + rt )
A - final amount 650 = 500 ( 1 + r * 3 ) /500
P - principal 650/500 = 1 + 3r
r - interest rate 1.3 = 1 + 3r
t - time ( in years) 3r = 0.3
r = 0.1 ( 10% ) 
