Question

17.(1) Find the sum of all two digit natural numbers which are divisible by 4
$sn = n \2(2a + (n - 1)d)$
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Answer 1

Answer:

1200

Step-by-step explanation:

all natural no. are

4,8,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68,72,76,80,84,88,92,96,100

and now add all of these

4+8+12+16+20+24+28+32+36+40+44+48+

52+56+60+64+68+72+76+80+84+88+92+96

=1200

Answer 2

Step-by-step explanation:

A.P: 12,16,20,..96

a=12,n=22,d=4

Sn=n/2(2a+(n-1)d)

Sn=22/2[2(12)+(22-1)4]

=11[24+(21)4]

=11[24+84]

=11[108]

=1188