In an A.P., if 15th term is 5 times the second term and 9th term exceeds the double of third term by 7 then its first term is
a) 9
b) 7
c) 4
d) 3​

Answer : n=72

Explanation: 7/8 n = 63
Multiply both sides of the equation by 8/7
8/7 x 7/8 n = 8/7 x 63
Reduce the numbers with the greatest common factor 8
1/7 x 7n = 8/7 x 63
Reduce the number with the greatest common factor 7
n=8/7 x 63
Reduce the number with the greatest common factor 7
n=8 x 9
Multiply the number
n=72
That’s how I got the answer