You have 10 numbers to choose from, and you're choosing 4 from that pool. Order of the numbers matters, because having 1234 as a PIN is not the same having it be 1324, so we're counting the number of permutations of 10 digits taken 4 at a time. So there are
possible PINs that can be made.
Answer:
As per the statement;
The moon takes 28 days to orbit around the earth going at a distance of 2,413,000 km
From the above information,
The ratio between Distance and Days is;
then,
the distance it takes for the moon to travel one day of its orbit around the earth we have;
km.
Therefore, the distance in kilometer does the moon cover in 1 day is 86178.57 km