Find out the missing term of the number series given below.

60, ?, 63.6, 70.8, 99.6, 243.6

The correct option is 61.2.

To find the missing term in the given series, let us analyze the differences between consecutive terms:

Given series: 60, ?, 63.6, 70.8, 99.6, 243.6

Let us calculate the differences between the known adjacent terms starting from the end of the series:

$243.6-99.6=144.0$

$99.6-70.8=28.8$

$70.8-63.6=7.2$

Now, let us examine the pattern among these differences:

$28.8\times 5=144.0$

$7.2\times 4=28.8$

Following this multiplication pattern backwards, the preceding multipliers should be 3 and 2:

Let the difference between 63.6 and the missing term (?) be $d_2$.

$d_2\times 3=7.2\Rightarrow d_2=2.4$

Let the difference between the missing term (?) and 60 be $d_1$.

$d_1\times 2=2.4\Rightarrow d_1=1.2$

Now we can calculate the missing term (?):

$?=60+d_1=60+1.2=61.2$

Verification using the next term:

$61.2+d_2=61.2+2.4=63.6$

Hence, the missing term is 61.2.