CA Foundation · Quantitative Aptitude · Equations
The sum of a positive number and its reciprocal is 10/3. What is the larger such number?
The larger number is 3. Writing x + 1/x = 10/3 gives 3x² − 10x + 3 = 0, whose roots are 3 and 1/3, and the larger one is 3.
- A1/3
- B2
- C3Correct
- D10/3
Explanation
Let x + 1/x = 10/3. Then 3x² − 10x + 3 = 0, which factors as (3x − 1)(x − 3) = 0. So x = 3 or 1/3. The larger is 3. Check: 3 + 1/3 = 10/3. The option 1/3 is the smaller root.
Did you get it right without looking?
One question tells you little. A timed set on Equations shows your real accuracy, how long you take and where you lose marks.
More Equations questions
- A train travels 120 km at a uniform speed. If its speed had been 10 km/h more, it would have taken 1 hour less for the journey. What is the …
- For what value of k will the system 2x + 3y = 7 and 4x + ky = 14 have infinitely many solutions?
- Solve the simultaneous equations 2x + 3y = 19 and x − y = 2. What is the value of x + y?
- The demand function for a product of Kisan Foods is p = 120 − 2q and the supply function is p = 30 + 3q, where p is price in rupees and q is…
- If α and β are the roots of the equation 2x² − 10x + 6 = 0, what is the value of α + β + αβ?
- What is the sum of all the roots of the cubic equation 2x³ − 6x² + 5x − 7 = 0?