SOLUTION: Luis invested $6000 in two different accounts. One earned 4% and the other earned 7%. He earned a total of $375 in interest in one year. How much was invested in each account?

Question 1149483: Luis invested $6000 in two different accounts. One earned 4% and the other earned 7%. He earned a total of $375 in interest in one year. How much was invested in each account?
Found 2 solutions by josmiceli, greenestamps:
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
For the 2 accounts
= amount invested in 4% account
= amount invested in 7% account
= interest from 4% account
= interest from 7%
= 1 year
----------------------------------------
For 4% account:
(1)
For 7% account:
(2)
----------------------------------------
By substitution:
(2)
(2)
(2)
and

------------------------------------
$1,500 = amount invested in 4% account
$4,500 = amount invested in 7% account
-----------------------------------------------
check:
(1)
(1)
(1)
and
(2)
(2)
(2)
(2)
OK
Answer by greenestamps(13198) (Show Source): You can put this solution on YOUR website!

If an algebraic solution is not required, then compare the amount of work required by this alternative method with that required with the standard algebraic solution shown by the other tutor.

$6000 all at 4% --> $240 interest
$6000 split between 4% and 7% --> $375 interest
$6000 all at 7% --> $420 interest

$375 is 3/4 of the way from $240 to $420. ($240 to $375 is $135; $240 to $420 is $180; 135/180 = 3/4. Picture the three numbers on a number line if it helps you see the 3/4.)

That means 3/4 of the investment is at the higher rate.

ANSWER: 3/4 of $6000, or $4500, at 7%; the other $1500 at 4%.

CHECK:
.07(4500)+.04(1500) = 315+60 = 375

RELATED QUESTIONS
Benjamin invested $12,000 in two CDs. One earned 4% and the other earned 6%. If he earned (answered by mananth)
Max invested $15,000 in two different funds. One earned 6% interest in the first year and (answered by Boreal)
62. Mrs. Chavez invested $6000. She invested the money in two accounts-one with a 4%... (answered by Mathtut)
Mr. Wilson invested money in two accounts. His total investment was $20,000. If one... (answered by ewatrrr)
Mr. Wilson invested money in two accounts. His total investment was $20,000. If one... (answered by ewatrrr)
Mr. Wilson invested money in two accounts. His total investment was $20,000. If one... (answered by ewatrrr)
Mr. Wilson invested money in two accounts. His total investment was $20,000. If one... (answered by mananth)
A man invests a total of in two savings accounts. One account yields 9% simple interest... (answered by stanbon)
A man invests a total of in two savings accounts. One account yields 9% simple interest... (answered by lynnlo)