Step-by-step explanation:
The hands of a clock point in opposite directions ( in the same straight line) 11 times in every 12 hours.
Answer:
315 miles
Step-by-step explanation:
90 times 3 plus 45
Let's assume that Kirby walks with a speed

for a time

, and that he runs with a speed

for a time

.
The total time available for Kirby to catch the train is:

and this must be equal to the sum of the two times t1 and t2:
The distance Kirby should cover is

and this should be equal to the sum of the distances covered by walking and by running:

So we have a system of 2 equations:


If we solve the system, we find:


So, Kirby needs to run at least for 8 minutes in order to catch the train.
You can see that the term
appears in both equations. In this cases, we can leverage this peculiarity and subtract the two equations to get rid of the repeated term. So, if we subtract the first equation from the second, we have

Now that we know the value of
, we can substitute in any of the equation to deduce the value of
: if we use the first equation, for example, we have
