Algebra Question Bank for C-CAT
Topic-wise Algebra MCQs for CDAC C-CAT preparation with answers and explanations.
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Correct Answer: C - 5
3x = 22-7 = 15. x = 5.
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Correct Answer: B - 29
x² + y² = (x+y)² - 2xy = 49 - 20 = 29.
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Correct Answer: D - 14
a² + 1/a² = (a + 1/a)² - 2 = 16 - 2 = 14.
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Correct Answer: B - 5
125 = 5³, so 125(1/3) = 5.
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Correct Answer: B - 6
64 = 26, so x = 6.
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Correct Answer: D - x + 3
x² - 9 = (x+3)(x-3). Dividing by (x-3) gives x+3.
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Correct Answer: B - 4
Adding equations: 4x = 16, x = 4.
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Correct Answer: A - 7 and 8
x + y = 15, xy = 56. Testing: 7 + 8 = 15, 7 × 8 = 56.
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Correct Answer: B - 2, 3
x² - 5x + 6 = (x-2)(x-3) = 0. x = 2 or 3.
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Correct Answer: C - 13
a² + b² = (a+b)² - 2ab = 25 - 12 = 13.
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Correct Answer: C - 11
x² + 1/x² = (x - 1/x)² + 2 = 9 + 2 = 11.
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Correct Answer: A - 4a(b+c)
Using a² - b² = (a+b)(a-b): = 2(b+c) × 2a = 4a(b+c).
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Correct Answer: B - 49
(x+y)² = x² + y² + 2xy = 25 + 24 = 49.
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Correct Answer: D - 4
Squaring both sides: x + 5 = 9. x = 4.
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Correct Answer: D - 2.301
log 200 = log(2×100) = log 2 + log 100 = 0.301 + 2 = 2.301.
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Correct Answer: B - 670
a = 5, d = 3. S₂₀ = 20/2 × [2(5) + 19(3)] = 10 × 67 = 670.
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Correct Answer: B - 2.5
4ˣ - 4ˣ/4 = 24. 4ˣ(1 - 1/4) = 24. 4ˣ × 3/4 = 24. 4ˣ = 32. x = 2.5.
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Correct Answer: B - 1536
a = 3, r = 2. T₁₀ = 3 × 2⁹ = 3 × 512 = 1536.
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Correct Answer: A - 5/6
1/α + 1/β = (α+β)/αβ = 5/6.
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Correct Answer: D - 7
a(logₐ x) = x. So 5(log₅ 7) = 7.
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Correct Answer: C - 23
(x+1/x)²=x²+2+1/x²=25. So x²+1/x²=23.
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Correct Answer: A - 12
3x-2x=5+7. x=12.
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Correct Answer: A - 58
(a+b)²=a²+2ab+b². 100=a²+b²+42. a²+b²=58.
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Correct Answer: D - 2
2(x+3)=25. x+3=5. x=2.
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Correct Answer: D - 2, 3
x²-5x+6=(x-2)(x-3)=0. x=2 or x=3.
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Correct Answer: D - 4
34=81. So x=4.
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Correct Answer: C - 4ab
(a+b)²-(a-b)²=a²+2ab+b²-a²+2ab-b²=4ab.
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Correct Answer: C - 5, -2
(x-5)(x+2)=0. x=5 or x=-2.
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Correct Answer: B - 4
Sum = -(-8)/2 = 4.
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Correct Answer: B - 12
Product = 12/1 = 12.
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Correct Answer: C - 32
x = 25 = 32.
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Correct Answer: D - 5, -2
2x-3=7 → x=5. 2x-3=-7 → x=-2.
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Correct Answer: B - 4
1/x=1/(2+√3)=2-√3. x+1/x=2+√3+2-√3=4.
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Correct Answer: C - x²+2x+4
x³-8=(x-2)(x²+2x+4). Divided by (x-2) = x²+2x+4.
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Correct Answer: A - -4
Let a=3k, b=5k. (3k+5k)/(3k-5k)=8k/-2k=-4.
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Correct Answer: A - x=7, y=3
Adding: 2x=14, x=7. y=10-7=3.
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Correct Answer: D - -8
D=b²-4ac=4-12=-8. Roots are imaginary.
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Correct Answer: A - 13
a²-b²=(a+b)(a-b). 39=3(a+b). a+b=13.
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Correct Answer: C - 2
5(2x-1)=53. 2x-1=3. x=2.
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Correct Answer: A - 3
f(2)=2(4)-3(2)+1=8-6+1=3.
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Correct Answer: C - 6
4-10+k=0. k=6.
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Correct Answer: C - 2
2x × 2(2x) = 26. 2(3x)=26. 3x=6. x=2.
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Correct Answer: D - 4
x+5=9. x=4.
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Correct Answer: A - 4n-1
a=3, d=4. nth term=3+(n-1)4=4n-1.
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Correct Answer: A - 670
a=5, d=3, n=20. S=20/2[10+19×3]=10[10+57]=670.
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Correct Answer: C - x=10
log(x)+2log(x)=3. 3log(x)=3. log(x)=1. x=10.
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Correct Answer: A - 6
f(2)=0. 8-2k+4=0. 2k=12. k=6.
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Correct Answer: A - 9
27(2/3) = (3³)(2/3) = 3² = 9.
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Correct Answer: D - 49
(x+y)²=x²+2xy+y²=29+20=49.
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Correct Answer: B - 2×3⁹
a=2, r=3. 10th term=2×39=39366.
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Correct Answer: B - 23
(x+1/x)2 = x2 + 2 + 1/x2 = 25, so required value is 23.
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Correct Answer: C - 58
a2+b2=(a+b)2-2ab=100-42=58.
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Correct Answer: B - 3, 4
x2 - 7x + 12 = (x-3)(x-4), so roots are 3 and 4.
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Correct Answer: B - 5
y=6-x. 2x-3(6-x)=7 gives 5x=25, so x=5.
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Correct Answer: A - 12:5
Let x=2k, y=3k. Ratio=(6k+6k):(8k-3k)=12k:5k=12:5.
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Correct Answer: A - x2 + xy + y2
x3-y3=(x-y)(x2+xy+y2).
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Correct Answer: B - 316.23 approximately
x=102.5=100 x sqrt(10), approximately 316.23.
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Correct Answer: B - 5
x2-6x+14=(x-3)2+5, minimum is 5.
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Correct Answer: C - 18
(x-1/x)2 = x2 -2 +1/x2 =16, so required value=18.
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Correct Answer: C - 24
Term with x2 is C(4,2)x2(2)2 = 6 x 4 = 24.