Question

Sum of 3 numbers in an A.P. is 3 and the product is -8. Find the difference between first and last terms.

• A. 1
• B. 2
• C. 4
• D. 6

Answer 1

The correct option is D 6

Let the three terms be a-d, a, a+d.
Sum $=a-d+a+a+d=3\to 3a=3\to a=1$
Product $=(a-d)\left(a\right)(a+d)=-8\to (1-d)(1+d)=-8\to 1-d^2=-8\to d^2=9\to d=\pm 3$
Difference $=(a+d)-(a-d)=2d=6$