Question

78,75,72 is ap so which term of this ap is first negative term

Answer 1

Answer:

28th term

Explanation:

Looking at the first term and second, we can clearly see that the common difference is -3. Also, 78 is perfectly divisible by 3 meaning it will reach at some point 6, 3, 0 and then -3 and so on.

$tn = a \: + \: (n - 1)d$

In this, plug in

$tn \: = 0 \\ a = 78 \\ d = - 3$

Solve it, you'll get n = 27 meaning 27th term is 0, then 28th term is the first negative term of the arithmetic progression.