Question

What is the sum of all two digit even natural numbe

Answer 1

Step-by-step explanation:

2 digit even natural no. are

10, 12, 14 ...... 98

here, a = 10 (smallest 2 digit even no)

d = 2 (common diffence between all no.)

tn = 98 (the last or largest no)

As tn = a+(n-1)d

98 = 10+(n-1)2

98-10/2 = n-1

88/2 = n-1

44+1 = n so, n = 45

sum of n terms = n/2 (2a+(n-1)d)

45/2(2×10+(45-1)2)

45/2 (20+88)

45/2 (108)

45 (54) == 2430.

so the total of all 2 digit even no will be 2430.