Question

which term of the arithmetic progression 3,10,17,........ will be 84 more than its 13th term?

Answer 1

Let the nth term be 84 more than the 13th term.Now a/q,a=3, d=10-3=7So, 13th term= a+12d =3+12x7=87Then nth term=84+87=171171=a + (n-1)d171=3 + (n-1)x7171-3/7+1=n168/7+1=n24+1=25=nTherefore 25th term of the ap will be 84 more than 13th term

Answer 2

a=3
d=7
13th term= a+12d
3+12(7)+84 =171
an= a+(n-1)d
171= 3+(n-1)7
171 -3 =(n-1)7
168/7= n-1
24+1= n
25=n