What will come in the place of question (?) mark in the following number series.

500, 50, 10, 3, 1.2 ?

The correct answer is 0.6.

To find the missing number in the given series, let us analyze the pattern or relation between consecutive terms:

Series: 500, 50, 10, 3, 1.2, ?

Let us look at the ratio of each term to the preceding term (or division factor):

1^st step: 500 ÷ 10 = 50

2^nd step: 50 ÷ 5 = 10

3^rd step: 10 ÷ 3.333... (or 10 ÷ ¹⁰/₃ = 3)

Alternatively, let us observe the operation applied to get each subsequent term:

500 × 0.1 = 50

50 × 0.2 = 10

10 × 0.3 = 3

3 × 0.4 = 1.2

Following this clear pattern, the next multiplier increases by 0.1 at each step:

1.2 × 0.5 = 0.6

Thus, the number that comes in place of the question mark (?) is 0.6.