Look Down Below For question:

The cattle train
speed - 36.5 km/h
time - x h

the passenger train
speed - 29.2 km/h
time - (2.4+x) h

The cattle train caught up to the passenger train so the distance they travelled is the same.
Distance is speed times time.



The passenger train travelled for 12 hours before the cattle train caught up.

Used brute force to figure this one out and got lucky at t=12.

What you need to know:



t = time travelled (in hours)

x = distance passenger train has travelled

y = distance cattle train has travelled

d = distance between both trains in km

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RESULTS AND TIME SNAPSHOTS:

When:

t=0, x=0, y=0, d=0

t=2.4, x=70.08, y=0, d=70.08

t=4.8, x=140.16, y=87.6, d=52.56

t=7.2, x=210.24, y=175.2, d=35.04

t=9.6, x=280.32, y=262.8, d=17.52

t=12, x=350.4, y=350.4, d=0 <-------

So your answer is 12 hours.

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.