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?

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.
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?

Please identify these problems. Thanks.

#FeatureRequests

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`a_{i-1}`	$a_{i-1}$
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`\sum_{i=1}^3`	$\sum_{i=1}^3$
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Comments

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?

Calvin Lin Staff - 6 years, 9 months ago

Thanks, Calvin.

Guiseppi Butel - 6 years, 9 months ago

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

Jon Haussmann - 6 years, 9 months ago

Thanks, Jon.

Guiseppi Butel - 6 years, 9 months ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$