# How to keep track?

I've had difficulties finding problems that I worked on and when I have the answer I can't find the problem.

Can you help me identify these problems?

1. 3 circles touch tangentially with diameters 3, 2, and 1. Find the radius of the largest circle that can be drawn in the space formed by the 3 circles.

2. Train leaves Canberra for Sydney at noon. Another leaves Sydney for Canberra forty minutes later. If each travel at the same rates taking 3 1/2 hours, what time do they meet?

Note by Guiseppi Butel
3 years, 9 months ago

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Problem 1 is Miscellaneous Problem Solving. One good way to keep track of problems you are working on is the "Save problem" feature.

- 3 years, 9 months ago

Thanks, Jon.

- 3 years, 9 months ago

You can use the search function at the top using select keywords. For example, question 2 is Easy #8.

I do not recall seeing question 1, and I can't find it either. Would you like to post it as a new question?

Staff - 3 years, 9 months ago

Thanks, Calvin.

- 3 years, 9 months ago