Practice30 Create account

In an arithmetic progression, the average of the first 8 terms is 19 and the average of the first 12 terms is 25. What is the common difference?

Competition practiceStatistics

A1.5
B6
C2
D3

Step-by-Step Solution

The average of the first

n

terms of an AP is

a + \frac{( n - 1 ) d}{2}

. So

a + 3.5 d = 19

and

a + 5.5 d = 25

; subtracting,

2 d = 6 \Rightarrow d = 3

.

Answer: D) 3

Master this topic in 30 minutes a day.

Don't just memorise the answer — build a daily practice habit.

Practice 5 Similar Questions Free →

All Statistics practice questions

More Statistics practice

Eleven numbers have a mean of 50. The mean of the first six is 49 and the mean of the…The mean of the squares of the first n natural numbers is 63. What is n?Two numbers have an arithmetic mean of 25 and a geometric mean of 15. What is the larger…Shreya logged her weekly running distance for 10 weeks; the mean was 18 km. When she…Five positive integers have a mean of 18 and a median of 20, and 22 is their only mode.…