Question

find the sum of all the two digits number which leave the remainder 2 when divided by 5​

Answer 1

Answer:

981

Step-by-step explanation:

The numbers are 12, 17, 22, ..., 97.

There are 18 of them and they are in an AP with first term a = 12 and common difference d = 5.

The sum of the first n terms of an AP is

na + n(n-1)/2 × d

so our sum is this with a = 12, d = 5, n = 18:

18×12 + 18×17/2 × 5

= 216 + 153×5

= 216 + 765

= 981

Answer 2

Answer:

Step-by-step explanation:

First two digit number who leave remainder 2 when divide with five is 12 and last number is 97.

an= 2+(n-1) * 5

97 - 2= (n-1) * 5

19= n-1

n=20

Sn=n/2*( a+l)

Sn=10(109)

Sn=1090