Question

What should come in place of the question mark ‘?’ in the following number series?

180, 174, 162, 144, 120, ?

1. 50
2. 60
3. 70
4. 80
5. 90

Answer 1

Correct Answer - Option 5 : 90

Considering the above series,

180, 174, 162, 144, 120, ?

The logic of the series can be explained as,

180 – (6 × 1) = 174

174 – (6 × 2) = 162

162 – (6 × 3) = 144 

144 – (6 × 4) = 120

By observing the pattern, we can write

120 – (6 × 5) = 90

⇒ ? = 90

∴ The value of ? is 90.