X + y = 2400
y = 3x
x + 3x = 2400
4x = 2400
x = 2400/4
x = 600 <== Mrs. Storey drove 600 miles
y = 3x
y = 3(600)
y = 1800 <== Mr. Storey drove 1800 miles
In this item, we are informed that the order of the entries does not matter in determination the number of ways in which the Archie can choose for his party. Because the arrangement or order is not important, this type of problem uses the concept of COMBINATION.
The equation for combination is,
nCr = n!/((n - r)!(r!))
nCr is read as "combination of n taken r".
Substituting the known values to the equation,
15C6 = 15! / ((15 - 6)!(6!))
= 5005
Hence, there are 5005 ways in which Archee can choose the 6 entrees for his party.
A regular polygon is a closed figure
All its angles are equal in measure.
and all its sides are congruent
