Question

7. Find the sum of all two-digit whole numbers divisible by 3.
8. Find the sum of all even numbers between 5 and 100.
atural numbers less than 100 which​

Answer 1

Answer:

As we know that,

an=a+(n−1)d.

∴99=12+(n−1)3.

⇒(n−1)387.

⇒n=29+1=30.

Sn=2n(a+l)

∴S30=230(12+99)

⇒S30=15×111=1665.