The way I figured this one out was saying that if it takes 2lbs to stretch it to 12 inches and 5lbs to stretch to 18 inches that means that 3 additional pounds = 6 inches. Therefore, each additional pound is 2 inches. We know already that with 2 lbs it was 12 inches in length and we can also say that 2 lbs = 4 inches. So subtract 4 from 12 and you end up with the answer of 8 inches.
The answer x = 11 is correct for problem 4. Nice work.
Use this x value to find the answer in problem 5. From problem 4, we're told that Romeo runs at a speed of 5 m/s. If he runs for x = 11 seconds,then he runs a total distance of:
5*x =(5 m/s)*(x meters) = (5 m/s)*(11 seconds) = 5*11 = 55 meters
The answer to problem five is 55 meters
Triangular prism: 2 bases and 5 faces
Pentagonal prism: 2 bases and 7 faces
0.6666 (repeating) x 0.75 = 0.5
0.6666 (repeating) / 0.75 = 0.8888888 (repeating)