Question

7th term of an arithmetic sequence is 15 and 13 term is 27.find 20th term​

Answer 1

Answer: 41

Step-by-step explanation:

Seventh term (t7) = 15 Thirteenth term (t13) = 27

t7 = 15

or, a + 6d = 15...(i)

t13 = 27

or, a + 12d = 27....(ii)

Now, subtracting (i) from (ii) we get:

a+12d-a-6d = 27-15

or, d = 2

again from (i), a = 15-6(2)= 15-12=3

20th term (t20) = a + 19d = 3 + 19(2) = 3+38= 41