hello all...

i have a question :

"John riding a bike from city A to city B. He departed at 07.00 am with speed of 60 kmph . From town A , Sisca followed with a speed of 80 kmph , what time Sisca followed John ?

the answer :

a) 10.00 am

b) 11.00 am

c) 12.00 am

d) 13.00 am

how to solve this problem with quickly method.

could you help me?

zidan3311

There is no such a time 13:00 am. eliminate this from your possible answer

Starting at 12:00 am means the second bicker started 7 hour

**before** the second bicker, contrary to the question. Eliminate this as a possible answer

You are left to choose between 11:00 am and 10:00 am. These are not the times to include in your equations.

Start by saying the two bickers covered the same distance. The fasted way you asked for is to find how many hours each bicker spent on the road.

Notice that 3*80 = 4*60 = 240 km

That means the first bicker spent 4 hours on the road to reach the encounter location. That was at 7 + 4 = 11:00 am

The second bicker spent only 3 hours to reach the encounter location. It must have started 1 hour afterward at 8 + 3 = 10:00 am

your answer should be a)