Phyllis invested a total of 7 dollars, spread across two accounts. one account has a simple interest rate of 5 percent per year. the second account has a rate of 6 percent per year. after one year, the total interest earned on these investments was 3870 dollars. how much money did she invest at each rate?

$33,000 invested in 5% account

$37,000 invested in 6% account

Step-by-step explanation:

Let amount invested in 5% be x

and amount invested in 6% be y

We can write:

0.05x + 0.06y = 3870

and

x + y = 70,000  [or x = 70,000 - y]

Replacing 2nd in 1st we get and solve:

0.05(70,000 - y) + 0.06y = 3870

3500 - 0.05y + 0.06y = 3870

0.01y = 370

y = 37,000

and x = 70,000 - 37,000 = 33,000

Thus,

$33,000 invested in 5% account

$37,000 invested in 6% account

d) 30 units^2

area of rectangle = l × b

we know,

length = 10 unit

breadth = 3 unit

applying the formula,

= l × b

= 10 × 3

= 30 unit^2

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