Simplification - Quantitative Aptitude (MCQ) questions for Q. 20728

Q.  In the quadratic equation ax2  - 11x + 40 = 0, if the sum of two roots is 1.1, what is the product of the two roots?
- Published on 07 Jul 17

a. 4
b. 4.2
c. 8
d. None of these

ANSWER: 4
 
The sum of the roots of the quadratic equation ax2 - bx + c = 0 are (-b/a) and the product of the roots are (c/a).
Thus, in the equation ax2 - 11x + 40 = 0, where a = a, b = - 11 and c = 40.
we get, sum of the roots = - (- 11) / a = 1.1
a = 11 / 1.1 = 10
Product of the roots = 40 / 10 = 4

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