Given that the First term of the Arithmetic sequence = -3
⇒ a = -3
We know that nth term of a Arithmetic sequence is : Tn = a + (n - 1)d
where a is the first term and d is the common difference
Given that 10th term is 15
⇒ T₁₀ = -3 + (10 - 1)d
⇒ -3 + (10 - 1)d = 15
⇒ 9d = 18
⇒ d = 2
⇒ Common difference of given Arithmetic Sequence is 2