How do I set this up, and can someone please walk me through the steps?
Lane invested $10,000, part at 15% and part at 14%. If the total interest at the end of the year is $1,430, how much did she invest at 15%?
2007-11-07 05:45:10 · 2 answers · asked by smiles4u 3 in Science & Mathematics ➔ Mathematics
let x=amount invested at 15%
let y=amount invested at 14%
x+y=10000
.15x+.14y=1430
solve first equation for x
x=10000-y
substitute this value for x into second equation
.15(10000-y)+.14y=1430
1500-.15y+.14y=1430
-.01y= -70
y=7000
therefore x=(10000-7000)=3000
2007-11-07 05:59:38 · answer #1 · answered by Mac 2 · 0⤊ 0⤋
let x be the amount of money invested for 15% interest
then (10000 - x) would be the amount for 14%
so the eq is
0.15 * 10000 + 0.14*(10000-x) = 1430
solve for x
2007-11-07 05:49:04 · answer #2 · answered by norman 7 · 1⤊ 0⤋