URGENT :Station X and Station Y are 150 km apart. A train departs from Station X and travels the first 126 km at a speed of 72 km/h before completing the remaining journey
to Station Y in 1 h. Find the average speed of the train for the whole journey.

I NEED IT BY TDY PLEASE HELP

Ibelieve the answer is c

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.