Question
In a classroom, the average score of 15 students on a
test is 44 points. If 5 new students, each with an average score of 'x' points, join the class, and 8 students, each with an average score of '(x β 6)' points, leave the class, the new average score of the 12 remaining students becomes '(x β 1)' points. What is the total score of these 12 students?Solution
ATQ, The sum of the score of 15 students on a test is = 44 Γ 15 = 660 The sum of the the score of 5 students is = 5 Γ a = 5a The sum of the score of 8 students is = 8(a β 6) = (8a β 48) The sum of the score of 12 students is = 12(a β 1) = (12a β 12) According to the question, 660 + 5a β (8a β 48) = 12a β 12 660 + 5a β 8a + 48 = 12a β 12 660 + 48 + 12 = 12a + 3a 720 = 15a a = 48 a = 48 Average score of 12 students is = 48 β 1 = 47 The sum of the score of 12 students is = 47 Γ 12 = 564
Find the perimeter of a sector which forms a central angle of 150Β° in a circle of radius 21 cm.
(Use Ο = 22/7)If the circumference of a circle is 352 cm then find the area of the circle?
A cylindrical drum has internal radius 2 m and height 3.5 m. Find its volume. Take Ο = 22/7.
In what time would a Cistern be filled by three pipes whose diameter are 2cm, 8/3 cm and 4cm running together, where the largest pipe alone fill it in 1...
A rectangular piece of copper foil of length 63 cm and area 1386 cm2 is folded along its width to form a cylinder such that there is only one...
The sum of the areas of a rectangle and a square is 432 cmΒ². The breadth of the rectangle is 6 cm more than each side of the square. If the length of t...
- The length of a rectangle is the same as the side of a square. If the area of the square is 625 mΒ² and that of the rectangle is 500 mΒ², what is the perim...
A right circular cylinder having total surface area of 2833.6 cm2 is immersed in a vessel completely filled with water. If the height of the ...
Inside a square land having perimeter equal to 120 metres, leaving aside a circular land of radius 14 metres, the remaining land needs to be levelled at...
If both the length and breadth of a rectangle are increased by 5 m, its area increases by 225 mΒ². The ratio of the perimeters of the square and rectang...
Relevant for Exams:
