Question

How many two digit nu are divisible by 3

Answer 1

Here numbers divisible by 3

12,15,18.......99

Here a=12

d=3

an=99

as we know

an=a+(n-1)d

99=12+(n-1)3

99-12=(n-1)3

87=(n-1)3

87/3=(n-1)

n-1=29

n=30

therefore two digit number divisible by 3=30