312 512
--------------|----------------------|------ A(s)
25 125 200 290
|--------------|---------|------------|------ B(s)
92 142
|------------------------|------------------- C(s)


Hello, my name is alex. I have read the requirements to asking for homework help. Here is a problem, I attempted about 30 times. First I post problem. Then I explain what I did.

Three digital clocks (A, B, and C) give simultaneous readings for four occasions. If two events are 600 seconds apart on clock A, how far apart are they on clock B? Clock C? When clock A reads 400 seconds what does clock B read? When clock C reads 15 seconds, what does clock B read?

I tried:
For 200 seconds (512-312) on A, B moves 165 (290-125). For 125 (200-25) on B, C moves 50 (142-50). I then made ratios to find answers.

200/165 = 600/x so x=495 On clock B it would be 495 apart.
On clock c:
125/50 = 495/x so x=198 On clock C it would be 198 apart.

When A=400, B=
200/165 = 400/x so x= 330 B= 330

When C=15, B=

125/50 = x/15 so x= 37.5 B=37.5

Did I attempt it correctly or make mistakes?

I think there are a couple of errors. First - your drawing didn't come through very clearly, so I have atempted to reconstruct it - please confirm if I have it right.

You wrote:
For 125 (200-25) on B, C moves 50 (142-50).

This should be: for 175 (200-25) on B, C moves 50 (142-92).

When events are 600 seconds apart on A, I agree that they are 600*165/200 = 495 seconds apart on B. But on C they are 495*50/175 = 141.43 seconds apart.

As for the next part, you can do it like this: When A = 400, that's the same as A= 312 + 88. You already know that 312 on A equals 125 on B. To that you need to add 88*165/200 = 72.6 seconds on B, so B will read 125+72.6 = 197.6 seconds.

Can you use this same approach for the question about what B reads when C = 15 seconds? Hint - the answer is a negative number.