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WBJEE Algebra Questions
Practise algebra (mathematics) for the West Bengal Joint Entrance Examination: 10 multiple-choice questions, each with the correct answer and a worked explanation. Click an option to check it, or “New questions” for another set.
Algebra practice
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Q1.Find the sum of the first 23 terms of the AP 15, 18, 21, …
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Answer: B — 1104
Sₙ = n/2 × [2a + (n − 1)d] = 23/2 × [30 + 66] = 1,104.
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Q2.Solve: x² − 8x − 9 = 0
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Answer: D — -1, 9
Find two roots with sum 8 and product -9: -1 and 9. So x² − 8x − 9 = (x + 1)(x − 9) = 0.
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Q3.Solve: x² + 3x − 4 = 0
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Answer: B — -4, 1
Find two roots with sum -3 and product -4: 1 and -4. So x² + 3x − 4 = (x − 1)(x + 4) = 0.
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Q4.Find the sum of the first 17 terms of the AP 13, 18, 23, …
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Answer: C — 901
Sₙ = n/2 × [2a + (n − 1)d] = 17/2 × [26 + 80] = 901.
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Q5.Find log₃ 27.
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Answer: B — 3
log_3(27) asks “3 to what power gives 27?” → 3^3 = 27, so the answer is 3.
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Q6.Solve: x² − 2x − 35 = 0
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Answer: B — -5, 7
Find two roots with sum 2 and product -35: -5 and 7. So x² − 2x − 35 = (x + 5)(x − 7) = 0.
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Q7.Find the sum of the first 17 terms of the AP 15, 24, 33, …
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Answer: B — 1479
Sₙ = n/2 × [2a + (n − 1)d] = 17/2 × [30 + 144] = 1,479.
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Q8.Find the sum of the first 12 terms of the AP 10, 15, 20, …
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Answer: C — 450
Sₙ = n/2 × [2a + (n − 1)d] = 12/2 × [20 + 55] = 450.
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Q9.Find log₃ 9.
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Answer: D — 2
log_3(9) asks “3 to what power gives 9?” → 3^2 = 9, so the answer is 2.
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Q10.Solve: x² − 9x + 14 = 0
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Answer: D — 2, 7
Find two roots with sum 9 and product 14: 2 and 7. So x² − 9x + 14 = (x − 2)(x − 7) = 0.
How to approach algebra questions
Factorise quadratics by finding two numbers with the right sum and product; check roots by substitution. For simultaneous equations, elimination is usually faster than substitution under time pressure.
About WBJEE
West Bengal Joint Entrance Examination — conducted by West Bengal Joint Entrance Examinations Board (WBJEEB). State engineering, technology and pharmacy entrance for West Bengal.
Original practice questions written for this site in the style and difficulty of each exam’s syllabus. They are not past papers and the site is not affiliated with any exam body. Exam patterns, marking schemes and syllabi change — always check the latest official notification.
WBJEE practice topics
| Topic | Section | Question source |
|---|---|---|
| Algebra | Mathematics | Calculated (new numbers every set) |
| Probability & Combinatorics | Mathematics | Calculated (new numbers every set) |
| Physics | Science | Calculated + question bank |
| Chemistry | Science | Calculated + question bank |