1/10 = 10/100
So we need to find 10% of 300.
0.10 x 300 = 30
It'd be 2 I think but I'm not good at math
Answer: a) 1977060966, b) 146581344.
Step-by-step explanation:
Since we have given that
There are 10 numbers,
There are 26 lower case letters,
There are 26 upper case letters,
Since the first 3 characters have to be digits and next 6 can be upper or lower.
So, a) repetitions are allowed:

b) repetitions are not allowed:

Hence, a) 1977060966, b) 146581344.
Use the equation
A= 2(wl +hl +hw)
Where
w is width
h is height
l is length