Algebra aptitude questions
Algebra questions are part of the Quant section of placement aptitude tests. Move all terms to one side and factor before reaching for a formula. Below are 5 worked examples with the answer and the working; practise ten fresh ones or take a timed mock when you are ready.
Example 1. What is the product of the roots of x^2 - 15x + 56 = 0?
- A. 15
- B. -56
- C. 56 (answer)
- D. 71
For ax^2 + bx + c = 0 the product of the roots is c/a. Here c = 56 and a = 1, so the product is 56 (the sum would be 15).
Example 2. If 2x + 7 = 17, what is the value of x?
- A. 5 (answer)
- B. 12
- C. 8.5
- D. 3.3
Subtract 7 from both sides: 2x = 10. Divide by 2: x = 5.
Example 3. What is the value of 21^2 - 5^2?
- A. 416 (answer)
- B. 676
- C. 437
- D. 256
Use a^2 - b^2 = (a - b)(a + b) = (21 - 5)(21 + 5) = 416.
Example 4. What is the value of 15^2 - 10^2?
- A. 125 (answer)
- B. 625
- C. 25
- D. 140
Use a^2 - b^2 = (a - b)(a + b) = (15 - 10)(15 + 10) = 125.
Example 5. If 5x + 13 = 38, what is the value of x?
- A. 7.6
- B. 10.2
- C. 5 (answer)
- D. 4.2
Subtract 13 from both sides: 5x = 25. Divide by 5: x = 5.
More Quant practice elsewhere: IndiaBIX, GeeksforGeeks. See the 60-day aptitude plan.