Question

If the sum of first $$n$$ terms of an A.P. is, $$\mathrm{S}_{n} = 5n^{2} + 3n$$, then its common difference is ______.

Options

• $$8$$

• $$10$$

• $$18$$

• $$26$$

Answer 1

If the sum of first $$n$$ terms of an A.P. is, $$\mathrm{S}_{n} = 5n^{2} + 3n$$, then its common difference is 10.

Explanation:

The nth term is $$\mathrm{S}_{n} - \mathrm{S}_{n - 1} = 10n - 2$$, so the common difference is $$10$$.