Question

Find the Number of terms in AP whose first term is 3 6th term is 23 and the sum of all the terms is 406

Answer 1

Answer:

Step-by-step explanation:

First term a=3, 6th a + 5d =23

Put a=3 into the equation of the 6th term

3 + 5d = 23

5d=23-3

5d= 20

d= 20/5

d= 4

Sum of all the a + (a+5d) = 3 + (3+5×4)

= 3 + (3+20)

= 3 + 23

= 26