Question

18. If the common difference of an A.P. is 5, then what is a 18 - a 13​

Answer 1

Answer:

Step-by-step explanation:

a18=a+[18-1]d

     =a+17d

a13=a+[13-1]d

     =a+12d

a18-a13=a+17d-a-12d

           =5d

           =5×5

           =25

Answer 2

Given

• Common Difference (d) = 5

To Find

→ a₁₈ - a₁₃

Solution

→ a₁₈ = a + (18 - 1)d

→ a₁₈ = a + 17d

→ a₁₃ = a + (13 - 1)d

→ a₁₃ = a + 12d

On substraction,

→ a₁₈ - a₁₃ = a + 17d - (a + 12d)

→ a + 17d - a - 12d

→ 5d = 5 × 5 [Given: d = 5]

→ 25

Answer

→ 25