You can ride your bike around your block twice and the whole neighborhood once in 10 minutes. You can ride your bike around your block twice and the whole neighborhood 4 times in 31 minutes. How long does it take you to ride around the neighborhood?

7 minutes

Step-by-step explanation:

okay so lets make blocks = x and neighborhood = y

2x + y =10

2x + 4y = 31

multiply the top equation by -1 so we can single out y

-2x - y = -10

2x + 4y = 31

combine the two equations

3y = 21

since the x's have canceled each other out, just divide both sides by 3 to get a single y

y = 7

70

step-by-step explanation: