Question

The sum of all even numbers between 0 and 30 is :
0 আৰু 30ৰ মধ্যৱর্তী যুগ্ম সংখ্যাবােৰৰ যােগফল হ'ব ?
a) 210.
| b 201
(c 212
(d 200
​

Answer 1

Answer:

a) 210

Step-by-step explanation:

2,4,6,8 = 20

12,14,16,18 = 20+40 (4*10) = 60

22,24,26,28 = 20+80 (4*20) = 100

10,20 = 30

Total = 210

Answer 2

Answer:

210

Step-by-step explanation:

The given series form as AS( series ), using the properties AP :

     nth term on AP = a + ( n - 1 )d       { where a is the first term and d is the common difference }

     Sum of first n terms : ( n / 2 )( a + l )        [ where l is the last term ]

Here,

     First term = a = first even number after 1 = 2

     Last term = l = even number just before 30 = 28

  For number of terms :  let the number of terms be n

 ⇒ 28 = 2 + ( n - 1 )2       { even number have a difference of 2, d = 2 }

 ⇒ 28 - 2 = ( n - 1 )2

 ⇒ 26 / 2 = n - 1

 ⇒ 13 + 1 = n

 ⇒ 14 = n

      Therefore,

Required sum = ( 14 / 2 )( 2 + 28 )

                  ⇒ 7( 30 )

                  ⇒ 210