Problema Solution
For the past year frank had a total of $1200 divided into 3 different savings accounts each one paying simple interest (one at 4% a second at 5% and a third at 6%) The total interest for the year was $56.00. The amount invested at 5% was $20 less than twice the amount invested at 6%. How much was in each account?
Answer provided by our tutors
Let the three different amounts invested be X, Y and Z
amount invested 1200 which is x+y+z= 1200
On X, 4% interest
on Y, 5% interest
on Z, 6% interest
total interest recieved is 56
Which forms (4/100)x+ (5/100)y+ (6/100)z=56
4x+5y+6z=5600
Y+20=2z
y=2z-20 put this in previous two equations we get
x+2z-20+z=1200 which becomes x+4z=1425
4x+5(2z-20)+6z=5600 which becomes 4x+16z=5700
Silving these two equations we get
z=205
Y=390
now x+y+z=1200
X+390+205=1200
X=605