There is a finite AP of n terms such that the difference between the last and first term when divided by (n-1), gives a quotient 12 and leaves no remainder. Find the common difference of this AP.
12
Let a1, be the first term, number of terms, common difference.
an = a1 + (n - 1)d
⇒ an - a1 = (n - 1)d
Dividing by (n−1)
⇒ an−a1n−1 = d which is the quotient and is equal to 12
∴d=12