Let's say that the value invested in the account with a rate of 8% is "x", then the amount invested in the account with a rate of 12% is:

To calculate the total interest we need to calculate the interest of each individual account and sum them:

The total interest is the sum of the two expressions above:

The value invested in the account with 8% interest is 830, the one invested in the account with 12% interest is 1280.
2(x+5) =20 is the translation
First add 13.2 to both sides to get 0.5x > 0.1x + 33.2.
Then subtract 0.1x from both sides to get 0.4x > 33.2.
Lastly, divide each side by 0.4 to get a final answer of x > 83.
Hope this helps!
A scale of 8cm:12cm would be a scale of 2/3. since this is the case, we can divide the scale drawing of the playground by the scale factor to get the length of the actual playground
12.4/0.6666 = 18.6
The answer is 18.6
I think is D
5^-2*25^-1
5^-2*5^-2
5^-4
1/5^4
1/625
0,0016, 5^-4