A copper wire is bent in the shape of a square of area 81 cm2. If the same wire is bent in the form of a semicircle, the radius (in cm) of the semicircle is
16
14
10
7
D.
7
Let the side of a square be x cm
∴ x2 = 81 cm
⟹
∴ Perimeter of a square = 9 x 4 = 36 cm
Now,
Perimeter of semi-circle = Perimeter of square
The volume (in m3) of rain water that can be collected from 1.5 hect of ground in a rainfall of 5 cm is
75
750
7500
75000
A can contain a mixture of two liquids A and B in the ratio 7 : 5. When 9 L of mixture are drawn off and the can is filled with B, the ratio of A and B becomes 7 : 9. Litres of liquid A contained by the can initially was
10
20
21
25
What number should be added to or subtracted from each term of the ratio 17 : 24 so that it becomes equal to 1 : 2?
5 is subtracted
10 is added
7 is added
10 is subtracted
The ratio of weekly incomes of A and B is 9 : 7 and the ratio of their expenditures is 4 : 3. If each saves ₹ 200 per week, then the sum of their weekly income is
₹ 3200
₹ 4200
₹ 4800
₹ 5600
Among three numbers, the first is twice the second and thrice the third. If the average of the three numbers is 49.5, then the difference between the first and the third number is
54
28
39.5
41.5
The mean of 50 numbers is 30. Later it was discovered that two entries were wrongly entered as 82 and 13 instead of 28 and 31. Find the correct mean.
36.12
30.66
29.28
38.21
A bicycle wheel makes 5000 revolutions in moving 11 km. Then, the radius of the wheel (in cm) is
70
35
17.5
140
The perimeter of a triangle is 40 cm and its area is 60 cm2. If the largest side measures 17 cm, then the length (in cm) of the smallest side of the triangle is
4
6
8
15
A shopkeeper allows a discount of 10% to his customers and still gains 20%. Find the marked price of the article which costs ₹ 450.
₹ 600
₹ 540
₹ 660
₹ 580