What is the area between two concentric circles of diameters 26cm and 20cm?
100\(\pi\)
169\(\pi\)
69\(\pi\)
9\(\pi\)
269\(\pi\)
Correct answer is C
Area of circle 1 with diameter 26cm:
\(\pi r^{2} = \pi \times (\frac{26}{2})^{2} \)
= \(169 \pi cm^{2}\)
Area of circle 2 with diameter 20 cm:
\(\pi R^{2} = \pi \times (\frac{20}{2})^{2}\)
= \(100 \pi cm^{2}\)
Area between the two circles = \((169 - 100) \pi cm^{2}\)
= \(69 \pi cm^{2}\)
Evaluate correct to 4 decimal places 827.51 x 0.015
8.8415
12.4127
124.1265
12.4120
114.1265
Correct answer is B
827.51 x 0.015 By normal multiplication or use of four figure table, 827.51 x 0.015 = 12.4127 (to 4 decimal places).
A cuboid has a diagonal of length 9cm and a square base of side 4cm. What is its height?
9cm
\(\sqrt{65}\)cm
\(4\sqrt{2}\)cm
7cm
6.5cm
Correct answer is B
Given a cuboid, the diagonal cuts a face of the cuboid into 2 right-angled triangles.
Hence, using the Pythagoras theorem, we have
\(9^{2} = 4^{2} + x^{2}\)
\(81 = 16 + x^{2}\)
\(x^{2} = 81 - 16 = 65\)
\(\therefore x = \sqrt{65} cm\)
Which of the following fractions is less than one-third?
\(\frac{22}{63}\)
\(\frac{4}{11}\)
\(\frac{15}{46}\)
\(\frac{33}{98}\)
\(\frac{122}{303}\)
Correct answer is C
All others are greater than 0.333 when converted to their fractions except \(\frac{15}{46}\)
29
26
24
25
23
Correct answer is B
Arranging the scores in ascending order:
12, 17, 25, 25, 25, 25, 26, 26, 26, 29, 29, 29, 35, 35.
The median is the average of the 7th and 8th marks.
= \(\frac{26 + 26}{2} = 26\)