Question

If the common difference of an ap is 3 find a 20 - a15

Answer 1

Answer:

15

Step-by-step explanation:

a20-a15=a+19d-a-14d

=5d

=5×3

=15

Answer 2

Answer:

Let the first term of the AP be a.

an = a(n − 1)d

a₂₀ – a₁₅ = [a + (20 – 1)d] – [a + (15 – 1)d]

= 19d – 14d

= 5d

= 5 × 3

= 15