Question

Can anyone help? Will give Brainly + 20 pts .

Answer 1

Answer:

She invested 1600 at 8%     (to get the shown $160 interest)

and $7400 at 10%    (to get the shown  640 interest)

If x = 4000 then $80 interest is x2 again = $160

and so forth $320 interest x 2 again = $640

Step-by-step explanation:

The format would always be for x and then where

investment - x = interest  we can work out totals this way and find x.

9000-x = 800  is first equation and substituted into 2nd equation;

0.10x+0.08(9000−x)=800

Use the distributive property to multiply 0.08 by 9000−x.

0.10x+720−0.08x=800

Combine 0.10x and  -0.08x to get 0.02x.

0.02x + 720 = 800

Subtract 720 from both sides.

0.02x=800−720

Subtract 720 from 800 to get 80.

0.02x=80

Divide both sides by 0.02.

x=  80 / 0.02

Make decimals numbers = 1 or above.

80  / 0.02    x 100

x=  8000 / 2

x = 4000