I don't know what you mean. "direct" and "indirect" variation are types of "proportions". There is no proportion here.
How do I do the following problem using direct/indirect variation method?
A train 210m long took 12 seconds to pass a 90m long tunnel. Find the speed of the train.
Using speed, distance & time formula, this can be easily done using the formula
Speed = Distance/Time
Speed = (210 + 90)/12
Speed = 300/12
Speed = 25 m/sec (or 90 km/hr)
But how do I do this problem using direct/indirect variation?
Thanks,
Ron