Question

5,9,13,17,.......sum of the 20th term of this ap is ​

Answer 1

Answer:

sum of the 20th term is 79.

Step-by-step explanation:

I hope it helps you out.

Answer 2

Step-by-step explanation:

step1: a=5( first term) , d= a2-a1= 9-5=4.(common difference) and n= 20.

step 2: sum for n terms -

sum= n*(2a+ (n-1)d)/2.

step3: sum = 20*(2*5 + (20-1)*4)/2

= 20*(10+76)/2

= 20*86/2

=860.