Question

If the common difference of an A.P is 3, then a20 -a15 is
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Answer 1

Answer:

Step-by-step explanation:

a = 1st term

d = 3

then a20 = a + (20 - 1) d = a + 19x3= a + 57 ......... i

      a 25 = a + 24 d = a + 24 x 3 = a + 72 ............................ ii

     as per question  i  -  ii

         a20  - a25 = a + 57 - a - 72

                           = - 15

Answer 2

Answer:

15

Step-by-step explanation:

a+19d-a-14d

=5d

=15