Lucy has a bag of marbles. She shares one third of them with Carol, keeping one quarter for herself. Amrita joins them, so Lucy

8 = 4N - 2.8. Add 2.8, leading to 10.8 = 4N. Divide 4, giving the population of Nevada as 2.7 million.

I couldn't write it out in detail, so the solution is 200. The work is visible in the image below if you need clarification. I hope this is useful to you!

The explanation is as follows: a visual attachment including the solution is provided.

The algebraic expression is 13x plus 27.

Multiply the two numbers, then find the square root.

3 * 147

441

sqrt(441)

21

The geometric mean equals 21.