Question

Find the 20 term from the end of the AP:3.8.13... 253​

Answer 1

Answer:

158

Step-by-step explanation:

Here a=3

common difference d=8-3=5

an=253

a+(n-1)d=253

putting values

3+(n-1)5=253

5(n-1)=253-3

5(n-1)=250

n-1=250/5

n-1=50

n=51

• we need to find 20th term from the the last term =51
• second last term=51-1
• =50term
• Third last term =51-2
• =49 term

so 20th term from last term=(51-19)the term

=32term

so we have to find a32

an=a+(n-1)d

putting values

a32=3+(32-1)5

=3+31*5

3+155

=158

so 20th term from the last term of the given Ap is 158