প্রশ্নে বলা হচ্ছে, ১টি ক্রমিক পূর্ণসংখ্যার গড় x. পরবর্তী দুটি সংখ্যা যুকত হলে গড় কত হবে?

Average of 5 consecutive
Number is 'x'
∴ The number is = (x - 2) ,(x-1),x,(x+1),(x+2)

∴ Sum of 5 consecutive number = 5× x = 5x

Next two number is (x + 3), (x + 4)

Sum of all number = 5x + (x + 3) + (x + 4) = 7x + 7

∴ Average of the number= (7x + 7)/7 = (7(x + 1))/7 = (x + 1)

∴ Average increased = x + 1 - x = 1

Let the ve consecutive number be a, (a + 1), (a + 2), (a + 3), (a + 4).

⇒ Average = (5a + 10)/5 = (a + 2)

⇒ x = (a + 2)

⇒ If next two number (a + 5) and (a + 6) is added,

⇒ Average = (7a + 21)/7 = (a + 3)

⇒ If next two numbers be added then average increased by 1

∴ The average is increased by 1 if next two number is included.

Short - trick - 

Let the number be 1, 2, 3, 4, 5

⇒ Average = 3

⇒ If next two number be taken,

⇒ Average = 4

∴ Average increased by 1.

(1+2+3+4+5)/5 = 3

(1+2+3+4+5+6+7)/7 = 4

4-3 = 1