Answers:
- <u>24000 dollars</u> invested at 4%
- <u>18000 dollars</u> was invested at 7%
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Work Shown:
x = amount invested at 4%
If she invests x dollars at 4%, then the rest (42000-x) must be invested at the other rate of 7%
She earns 0.04x dollars from that first account and 0.07(42000-x) dollars from the second account
This means we have
0.04x+0.07(42000-x)
0.04x+0.07*42000-0.07x
0.04x+2940-0.07x
-0.03x+2940
This represents the total amount of money earned after 1 year.
We're told the amount earned in interest is $2220, so we can say,
-0.03x+2940 = 2220
-0.03x = 2220-2940
-0.03x = -720
x = -720/(-0.03)
x = 24000 dollars is the amount invested at 4%
42000-x = 42000-24000 = 18000 dollars was invested at 7%
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As a check, we can see that
18000+24000 = 42000
and also
0.04x = 0.04*24000 = 960 earned from the first account
0.07*18000 = 1260 earned from the second account
1260+960 = 2220 is the total interest earned from both accounts combined
This confirms our answers.
An equation that correctly represent this relationship if x represents the number of pounds of fertilizer and y the number of ounces of weed killer is 0.5x + 3.5y = 70
<u>Solution:</u>
Given that, Bill spent 70 on fertilizer and weed killer for his lawn
Each pound of fertilizer cost 50 cents and each once of weed killer cost 3.50
We have to write an equation, if x represents the number of pounds of fertilizer and y the number of ounces of weed killer.
Now,<em> total amount = amount for fertilizers + amount for weed killers.</em>
Total amount = number of pounds of fertilizers x cost per pound + number of ounces of weed killer x cost per ounce.
Hence, the equation is 0.5x + 3.5y = 70
$200 divided by 100 customers = 2$.
So, if he wants to make a profit of $200, he would have to make each customer pay $2. :)
