Question

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?

Answer 1

7 minutes

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