Question

For what value of n ,nth term of the A.P. 63 ,65,67and 3,10,17 are equal?

Answer 1

for 1st series - 63,65,67
a=63 n=? & d=2
for 2nd series -3,10,17
a=3 n=? & d=7
according to question
nth term of 1st series = nth term of second term
so,
63+(n-1)2=3+(n-1)7
63+2n-2=3+7n-7
2n+63=7n-4
2n-7n=-4-61
-5n=-65
n = -65/-5
n = 13