Log (40^{2} - 20^{2}) is equal to

- log 3
- log 60 + log 20
- log 40 – log 20
- log 20

**Solution**

(a^{2 }- b^{2}) = (a-b)(a+b)

(40^{2} - 20^{2}) = (40-20)(40+20) = 20*60

Now using product property of log

Log (a*b) = Log a + Log b

Log (20*60) = Log 20 + Log 60

**Correct option is B.**