A father's age is three times his son's. Their combined age is 44 years. Find the son's age.
Correct answer: C
Let the son's age be x. Then x + 3x = 44, so x = 11.
0 correct out of 0 attempted (0%)
Correct answer: C
Let the son's age be x. Then x + 3x = 44, so x = 11.
Correct answer: D
(6−2)×180=720.
Correct answer: C
Three of six outcomes are even, so the probability is 1/2.
Correct answer: A
I is correct: the area in square centimetres of a triangle with base 14 cm and altitude 9 cm → 63. Area=½×14×9. II is incorrect: the volume in cubic centimetres of a cube with edge 4 cm → 64. Volume=4³.
Correct answer: B
Choose two: 5×4/2=10.
Correct answer: C
I is incorrect: the circumference in centimetres of a circle of radius 7 cm, using π=22/7 → 44. C=2πr=44. II is incorrect: the tenth term of 3,7,11,... → 39. a10=3+9×4.
Correct answer: A
Each exterior angle is 360/8.
Correct answer: C
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 sum of the first ten terms of 2,4,6,... → 110. The sum is 2(1+...+10)=110.
Correct answer: B
Six faces each have area 9.
Correct answer: D
I is correct: x+y when x−y=4 and x+y is twice x−y → 8. The sum is 2×4. II is incorrect: the positive root of x²−5x−14=0 → 7. The expression factors as (x−7)(x+2).
Correct answer: B
Volume=πr²h=(22/7)×9×7.
Correct answer: D
I is incorrect: the sixth term of 2,6,18,... → 486. The geometric sequence gives 2×3^5. II is incorrect: the exterior angle in degrees of a regular octagon → 45. Each exterior angle is 360/8.
Correct answer: A
There are 4!=24 permutations.
Correct answer: D
I is incorrect: the volume in cubic centimetres of a cube with edge 4 cm → 64. Volume=4³. II is incorrect: the sum of the first ten terms of 2,4,6,... → 110. The sum is 2(1+...+10)=110.
Correct answer: B
The sum is 2×4.
Correct answer: C
I is incorrect: the area in square centimetres of a circle of diameter 14 cm, using π=22/7 → 154. Radius is 7, so area=π×49=154. II is incorrect: x satisfying 3x+7=31 → 8. 3x=24, so x=8.
Correct answer: B
a10=3+9×4.
Correct answer: D
I is incorrect: the number of two-person teams from five distinct people → 10. Choose two: 5×4/2=10. II is incorrect: the number of ways to arrange four distinct books in a row → 24. There are 4!=24 permutations.
Correct answer: C
Pythagoras gives √(25+144)=13.
Correct answer: B
I is incorrect: x²+y² when x+y=10 and xy=21 → 58. (x+y)²−2xy=100−42. II is incorrect: the interior-angle sum in degrees of a hexagon → 720. (6−2)×180=720.
Correct answer: D
Radius is 7, so area=π×49=154.
Correct answer: C
I is correct: the smaller root of x²−9x+20=0 → 4. The roots are 4 and 5. II is incorrect: the tenth term of 3,7,11,... → 39. a10=3+9×4.
Correct answer: B
The sum is 2(1+...+10)=110.
Correct answer: A
I is correct: the volume in cubic centimetres of a cube with edge 4 cm → 64. Volume=4³. 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: B
(x+y)²−2xy=100−42.