The trip there took 7 hours. The trip back took 10. What was the plane's speed on the way there if it went 210 kilometres per hour on the return trip? Please help I'm desperately confused.

Since you are unable even to begin, I'll assume that you missed the class(es) when this was covered, and need lesson instruction.

This topic is often referred to as a "uniform rate" or "uniform motion" exercise, using the equation "d = rt". You can find loads of lessons online, such as

__this one__, which explain how to set up and solve these sorts of exercises. Please study

*at least two* from

__this list__. Once you have learned the basic terms and techniques, please attempt the exercise.

If you get stuck, please reply showing your thoughts and efforts so far, starting with the variables you picked, and how you defined them. Thank you!