Maria invested $5000, some at 6% and some at 9%. If she wins $393 annual interest how much is invested in each account.

Ok, so

We could solve this problem using a system of linear equations as follows:

x = amount invested at 6%

y = amount invested at 9%

We are given two numbers in the problem:

$5000 = total money invested in both accounts

$393 = total interest earned in both accounts

Then we could write:

This system can be solved using sustitution:

Replacing:

And y = 5000 - x, which is 5000 - 1900, and that is 3100.

We obtain that the solution of the system is:

Therefore, there was invested $3100 in the account at 9% and 1900 in the account at 6%.

$54.99

step-by-step explanation:

$54.99 includes 500 min. if she does not exceed 500 min then her bill is $54.99

d. $180

step-by-step explanation:

if the dimensions of the room is 9ft by 12 ft, we have the area of the floor as,

so the area of the floor is 108 square feet, converting that into square yards we get,

the cost of carpet is $15 per square yard, therefore the cost of carpet for 12 square yards is,

hence, the cost of carpet is $180.

assuming the dimensions of the room be,

15 ft by 12 ft

so, the area of the floor of that room is,

we can convert 180 square feet into square yards, we know that,

1 sq ft = 0.111 sq yard

so, 180 square feet is,

so the area of floor is 20 square yards.

now, the cost of carpet is 15 dollars per square yard, therefore the cost of carpet for 20 square yards is,

so, it will cost $300.