Which term of the progression $20, 19 \frac{1}{4},18\frac{1}{2} ,17\frac{3}{4}$... is the first negative term

Which term of the progression $20, 19 \frac{1}{4},18\frac{1}{2} ,17\frac{3}{4}$... is the first negative term?

Answer

Here d = $\frac{-3}{4}$

Let the nth term be first negative term 

20(n - 1) $(\frac{-3}{4}\right)$

3n > 83

$$ n > 27\frac{2}{3} $$

Hence, 28th term is first negative term.