You invest $2,500 in each of two accounts. account a earns a simple interest at a rate of 4% over 3 years. account b earns a simple interest at a rate of 6% over 21 months. find the interest earned by each accounts.

Interest on A = $300 , Interest on B = $262.5

Step-by-step explanation:

  Formula for finding simple interest

 I = P x R x T

       , Where P = Principal Invested., R = Interest Percentage and

         100

T = Time or duration of the investments.

Account  (A) simple interest =

I  = 2,500 x 4 x 3

              100

    = 25 x 12

    = 1200/4

    = $300

Therefoe account A interest at the end of the 3rd year = $300

Now for account ( B ) at te same principal of $2,500

 I = 2,500 x 6 x 21 months

         , Please bear in mind that the 21 months needs to

                  100,

to be converted to year because the formula only obey years and not in months

Therefore, the 21 years = 1 year 9 months since 12 calender months makes a year. Now , 9 month therefore is 3/4 of a year, so

21 months  = one three quarter of a  year.  ( 1³/₄ )

21 months =    7/4 converted to improper fraction.

     Now substitute this in the formula above

I  = 2500 x 6 x 7

         100 x 4

   =  25 x 21

           2

  =   2100

        2 x 4

  =  2100

         8

  =  $262.5

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1