Question

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

• A. 18th
• B. 22nd
• C. 28th
• D. 29th

Answer 1

The correct option is C

28th

$a_n$<0
a=20,d=$-\frac{3}{4}$
put the above value in equation
$20+\frac{(-3n+3)}{4}$ < 0
we get 3n > 83
Using formula,
So, $n\ge 28$