Maths question from Laboratory Attendant exam, 2026 by JKSSB
The sum of the 3rd and the 4th term of an A.P. is 19 and that of the 1" and the 7 term is 22. Find the 9th term.
Last updated Jun 19, 2026
Correct Answer:
Option D —
26
An arithmetic progression is just a sequence of numbers where you add the same value (let's call it the "step size") to get from one number to the next.
Look at the clues given:
The sum of the third and fourth numbers in the list is 19.
The sum of the first and seventh numbers in the list is 22.
Find the step size:
If you write out the math in words, the combination of the first and seventh numbers contains the exact same starting values as the third and fourth numbers, but it includes one extra step size.
Because that second combination totals 22 instead of 19, that single extra step must be worth the difference between 22 and 19.
Therefore, the step size is 3.
Find the starting number:
Since we know the step size is 3, we can work backward. The combination that makes 19 is made of two copies of the starting number plus five steps.
Five steps of 3 equals 15.
To get from 15 to 19, we need 4 more. Since that 4 is shared equally between two copies of the starting number, the starting number must be 2.
Find the ninth number:
To get to the ninth number in the list, you start with your first number (2) and add the step size (3) eight times.
Eight steps of 3 equals 24.
Adding your starting number of 2 gives you a final answer of 26.
Answer verified by Quintessence Classes faculty — Karan Nagar, Srinagar.
