Mathematics MCQ — 249 Practice Questions with Answers

Explanation

The sum of the data is 122, so the mean is 122/8 = 15.25. Arranged in order, the data are 3, 4, 6, 7, 12, 16, 35, 39; the median is (7+12)/2 = 9.5. The difference is 15.25 - 9.5 = 5.75, so option C is correct.

Explanation

Population growth is compounded yearly, so the population after 2 years is 50000(1 + 2/100)^2. This equals 50000 × 1.0404 = 52,020. Therefore option A is correct.

Explanation

The surface area of a sphere is 4 pi r squared and its volume is 4/3 pi r cubed. Equating their numerical values gives 4 pi r squared = 4/3 pi r cubed, so r = 3. Hence the radius is 3 units, which is option B.

Explanation

The ceiling area is ₹5000/₹25 = 200 m². If breadth is b and length is 2b, then 2b² = 200, so b = 10 m and length = 20 m. The four-wall area is ₹64800/₹240 = 270 m², and 2(l + b)h = 2(20 + 10)h = 270, giving h = 4.5 m; hence option B is correct.

Explanation

The third proportional to 8 and 12 is found from 8 : 12 = 12 : x, so x = 12²/8 = 18. The mean proportional between 4 and 9 is √(4 × 9) = 6. Their ratio is 18 : 6 = 3 : 1, so option A is correct.