Five people can finish painting a wall in 5 hours.if only 2 people are available,how many hours do they have to work to finish t
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Answer:
There are 3478761 ways to select the first 5 numbers
Step-by-step explanation:
As understood from the statement of this problem we assume that it does not matter the order in which the first 5 white balls are selected.
In this case it is a combination.
So, what we want to know is how many ways you can choose 5 white balls out of 55.
Then we use the formula of combinations:
Where you have n elements and choose x from them.
Then we look for:
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.
for a time
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.