Question

the 1st ,2nd and last terms of an ap are respectively 4,7 and 31 how many terms are there in the Ap?​

Answer 1

Answer:

Given: a=4 ; a2=7; l=an=31

d= a2-a1

d= 7-4

d=3

an = a+(n-1)d

31= 4+(n-1)3

27=(n-1)3

9=(n-1)

n=10

hope it helps u.......^_^

Answer 2

Given:

We have first term of A.P is 4, Last term of A.P is 31.

To FInd:

We have to find the number of terms?

Step-by-step explanation:

• We have First term of A.P is , a =4

• Second term of A.P is,$a_2$=7

• Now common difference of A.P is caculated by the formula

                   $d=a_2-a_1=7-4=3$

• We have last term of A.P is 31

• We know nth term of A.P is given by the formula

                   $a_n=a+(n-1)d$

• Now we will put the values a=4, d= 3 in the above equation we get

                  $31=4+(n-1)3\\31-4=(n-1)3\\27=(n-1)3\\n-1=\frac{27}{3} =9\\n=9+1=10$

Hence, the term will be 10th term.