0 correct out of 0 attempted (0%)
Correct answer: B
I is correct: the number of ways to arrange four distinct books in a row → 24. There are 4!=24 permutations. II is incorrect: the circumference in centimetres of a circle of radius 7 cm, using π=22/7 → 44. C=2πr=44.
Correct answer: A
Area=½×14×9.
Correct answer: B
I is incorrect: the volume in cubic centimetres of a cube with edge 4 cm → 64. Volume=4³. II is incorrect: the interior-angle sum in degrees of a hexagon → 720. (6−2)×180=720.
Correct answer: A
The geometric sequence gives 2×3^5.
Correct answer: B
I is incorrect: the smaller root of x²−9x+20=0 → 4. The roots are 4 and 5. II is incorrect: the volume in cubic centimetres of a cylinder with radius 3 cm and height 7 cm, using π=22/7 → 198. Volume=πr²h=(22/7)×9×7.
Correct answer: D
The expression factors as (x−7)(x+2).
Correct answer: A
I is correct: x²+y² when x+y=10 and xy=21 → 58. (x+y)²−2xy=100−42. II is incorrect: the total surface area in square centimetres of a cube with edge 3 cm → 54. Six faces each have area 9.
Correct answer: B
3x=24, so x=8.
Correct answer: A
I is correct: x²+y² when x+y=10 and xy=21 → 58. (x+y)²−2xy=100−42. II is incorrect: the sixth term of 2,6,18,... → 486. The geometric sequence gives 2×3^5.
Correct answer: C
Volume=4³.
Correct answer: A
I is correct: x²+y² when x+y=10 and xy=21 → 58. (x+y)²−2xy=100−42. II is incorrect: the positive root of x²−5x−14=0 → 7. The expression factors as (x−7)(x+2).
Correct answer: A
C=2πr=44.
Correct answer: A
I is incorrect: x satisfying 3x+7=31 → 8. 3x=24, so x=8. II is incorrect: the total surface area in square centimetres of a cube with edge 3 cm → 54. Six faces each have area 9.
Correct answer: D
The roots are 4 and 5.
Correct answer: A
Use a²+b² = (a+b)² − 2ab = 11² − 2 × 13.
Correct answer: B
The roles differ. Choose the captain in 4 ways and deputy in 3 ways.
Correct answer: B
The five equally spaced values have mean equal to the middle value 15.
Correct answer: B
Upstream speed = still-water speed − stream speed = 11 − 3.
Correct answer: C
I is incorrect: annual simple-interest rate in percent if Rs 1500 earns Rs 450 in 5 years → 6. Rate=450×100/(1500×5). II is incorrect: the commission in rupees at 3% on sales of Rs 18000 → 540. Commission=18000×3/100.
Correct answer: A
Profit divides 3:5, so the first receives 1600×3/8.
Correct answer: C
I is incorrect: marked price in rupees if a 20% discount leaves a selling price of Rs 960 → 1200. Marked price=960/0.8. II is incorrect: the net receipt in rupees from Rs 2400 after a 2.5% service deduction → 2340. The deduction is 60, leaving 2340.
Correct answer: A
I is correct: annual simple-interest rate in percent if Rs 1500 earns Rs 450 in 5 years → 6. Rate=450×100/(1500×5). II is incorrect: the number of years for simple interest to equal principal at 8% per year → 12.5. Pt×8/100=P gives t=100/8.
Correct answer: C
Unit cost is 70, so seven cost 490.
Correct answer: D
I is incorrect: the value in rupees of a Rs 10000 asset after two annual depreciations of 10% → 8100. 10000×0.9²=8100. II is incorrect: compound interest in rupees on Rs 1000 at 10% annually for 2 years → 210. Amount=1000×1.1²=1210; interest=210.
Correct answer: D
The customer pays 0.9×0.8=72% of the marked price.