Hi there! I'm kind of confused about how to solve this!

Each ladder had 30 rungs.
Bob went down two rungs every second.
Roy went up one rung every second.
At some point, Bob and Roy were at the same height. Which rung were they on?

The answer is the 10th rung, but do I solve this using equal values, substitution, or the elimination method?

Use the spider tool located on page 1 of this activity to draw a 12-pointed star for the new logo. (hint: if the spider rotates 360 degrees -- or 720 degrees or 1080 degrees -- she will be facing in the same direction in which she started. when the spider is done drawing, you want her to be facing in the same direction in which she started. she'll be making 12 rotations, all the same size, so each rotation must be some multiple of 360/12 = 30 degrees.) urgently. been stuck on this problem for around 45 minutes now.! it should be easy if you're smart enough