CA Foundation · Quantitative Aptitude · Equations
If the equations x + 2y = 7 and 3x − y = 7 are solved, what is the value of 2x − 3y?
The value of 2x − 3y is 0. Solving gives x = 3 and y = 2, which satisfy both equations, so 2(3) − 3(2) = 0.
- A−1
- B1Correct
- C0
- D3
Explanation
From x + 2y = 7, x = 7 − 2y. Then 3(7 − 2y) − y = 7 gives 21 − 7y = 7, so y = 2 and x = 3. Hence 2x − 3y = 6 − 6 = 0, which matches option 3, not option 2. Check: 3 + 4 = 7 and 9 − 2 = 7. The value is 0.
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
- The sum of the ages of a father and his son is 60 years. Six years ago, the father's age was 7 times the son's age. What is the present age …
- A manufacturer in Coimbatore has fixed costs of ₹60,000 per month. The variable cost is ₹40 per unit and each unit is sold for ₹55. How many…
- A fixed cost of ₹12,000 is incurred by Sharma Traders each month, and the variable cost is ₹20 per unit. Each unit sells for ₹32. How many u…
- Anita is 4 times as old as her son today. After 6 years she will be 3 times as old as him. What is Anita's present age?
- For the cubic equation x³ − 7x + 6 = 0, what is the sum of the squares of its roots?
- If α and β are the roots of 2x² − 9x + 4 = 0, what is the value of α² + β²?