Question

Q7. The sum all even natural numbers between 1 and 31 is:
A. 16
B. 128
C. 240
D. 512​

Answer 1

Step-by-step explanation:

Let Sn = (2 + 4 + 6 + 30). This is an A.P. in which a = 2, d = 2 and l = 30

Let the number of terms be n Then,

a + (n - 1)d = 30

⇒ 2 + (n - 1) x 2 = 30

⇒ n = 15

∴Sn=n2(a+I)

=152×(2+30)

=15×16

=240

Answer 2

Answer :

• Even Natural Numbers between 1 and 31 are
• 2
• 4
• 6
• 8
• 10
• 12
• 14
• 16
• 18
• 20
• 22
• 24
• 26
• 28
• 30

• Sum of all even natural numbers is
• 2+4+6+8+10+12+14+16+18+20+22+24+26+28+30
• >>240

Therefore,

Sum of all even natural numbers between 1 and 31 is 240