A total of $6000 is invested: part at 7 % and the remainder at 15%. How much is invested at each rate if the annual interest is $710?

15% = $5100

7% = 900

Step-by-step explanation:

With simultaneous equations we can take the easier number like numbers that end in 0 or 5 or 2 etc.

We have 7% which is a prime and 15 so we call and name 'x' = amount

invested at 15%

x = the amount invested at 15%

Then 6000-x = the amount invested at 7%

The total interest earned is $710.

Therefore solve the simultaneous equation by substituting the 6000-x

0.15x + 0.08 (6000-x) = 710

Solve for x:

0.15x - 0.07x + 353 = 780 -> x = 357/0.07= $5100

Therefore the amount invested at 7% interest = 6000 - 5100 = $900

and here, 6000-900 = 5100 = 15%

it’s the first one your welcome