SOLUTION: Janet invested $31,000, part at 10% and part at 1%. If the total interest at the end of the year is $1,390, how much did she invest at 10%? please help thanks

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Question 127324: Janet invested $31,000, part at 10% and part at 1%. If the total interest at the end of the year is $1,390, how much did she invest at 10%?
please help thanks

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = the part of $31,000 invested at 10%
Then 31000+-+x will be the amount invested at 1%
.1x+%2B+.01%2831000+-+x%29+=+1390
.1x+%2B+310+-+.01x+=+1390
.09x+=+1080
x+=+12000
$12,000 was invested at 10% answer
check:
.1x+%2B+.01%2831000+-+x%29+=+1390
.1%2A12000+%2B+.01%2831000+-+12000%29+=+1390
1200+%2B+.01%2A19000+=+1390
1200+%2B+190+=+1390
1390+=+1390
OK