Explain how you can mentally determine that 35000 divided by 70 is 500

Liam's parents are driving three times as fast as liam is biking, but they left later than he did. if his parents caught up with him two hours after he left, how much later than liam did they leave?

Aline has a slope of 1/4 and passes through point (0.4,-1/2). what is the value of the y-intercept?

Jack has a piece of red ribbon that is two times as long as his piece of blue ribbon. he says that he can use two different equation to find out how long his piece of red ribbon is compared to his piece of blue ribbon is. is he correct? explain his reasoning