Correct Answer - Option 1 : It shall increase by 1
Given -
The average of five consecutive number is x
Formula used -
Average = (sum of all observation)/(number of observation)
Concept used -
If odd number of terms given then average is the middle number.
Solution -
Let the five 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.
