Question

A and B start from the same place in opposite directions with 25kmph and 30kmph in what time they will be 110 km apart?

Answer 1

Answer:

Explanation:

Let Da=distance travelled by A: Da=25t and Db=distance travelled by B: Db=30t, but Da+Db=110.

Substitute the values of Da and Db: 25t+30t=110km

55t=110; t=110/55= 2 hours (answer)

Answer 2

Answer:

They are moving apart at 25 + 30 = 55 kmph, relative to each other. They will be 110 km apart after 110/55 = 2 hours.

What is the point of this question? Some questions are quite tricky, but this one is straight forward.

Explanation:

Let Da=distance travelled by A: Da=25t and Db=distance travelled by B: Db=30t, but Da+Db=110.

Substitute the values of Da and Db: 25t+30t=110km

55t=110; t=110/55= 2 hours (answer)