HomeTestsSearchRankProfile
mediumMCQUPTET Paper 2 (Maths & Science)2017Mathematics and Science
1 mark

If the roots of the equation x
2
−px+54=0 are in the ratio 2:3, then the value of p is

  1. A
    18
  2. B
    51
  3. C
    -21
  4. D
    15

Solution & Step-by-step Explanation

Let the roots of the quadratic equation x
2
−px+54=0 be α and β.
Given that the ratio of roots is α:β=2:3, we can define the roots as:

α=2kandβ=3k
From the standard relationships of a quadratic equation:

Product of roots:

α×β=
a
c

⟹(2k)×(3k)=54
6k
2
=54
k
2
=9⟹k=±3
Sum of roots:

α+β=−
1
(−p)

=p
2k+3k=p⟹5k=p
Case 1: If k=3, then p=5(3)=15.

Case 2: If k=−3, then p=5(−3)=−15.

Looking at the options provided, 15 is present in option D.

Practice this question

Try it yourself before checking the explanation above.

If the roots of the equation x
2
−px+54=0 are in the ratio 2:3, then the value of p is
A
18
B
51
C
-21
D
15

Share This Question

Related Questions

Ready for a Full Test?

Practice with timed mock tests and track your performance across Mathematics and Science.

Discussion