Question
A 120-litre mixture contains 25% alcohol. How many
litres of alcohol should be added so that alcohol becomes 40% of the final mixture?Solution
ATQ,
Initial quantity of alcohol = 0.25 × 120 = 30 litres Let the required alcohol to add = y litres So, (30 + y) ÷ (120 + y) = 40/100 = 2/5 ⇒ 5(30 + y) = 2(120 + y) ⇒ 150 + 5y = 240 + 2y ⇒ 3y = 90 ⇒ y = 30
A room 20 m long, 16 m broad and 8m high has 2 windows of 1 m and `1(1)/(2)` m and a door of 2m `xx` `1(1)/(2)` m. Find the cost of paperi...
The diagonals of a rhombus are 16 cm and 12 cm. What is the perimeter of the rhombus?
The ratio of the length of a rectangle, breadth of the rectangle and the diameter of a circle is 10:8:4. If the area of the circle is 154 cm^2 , then wh...
A cube of side 14 cm is immersed completely in a cylindrical vessel of radius 10 cm. What will be the rise in the water level in the vessel due to the i...
The number of females working in the Production department forms approximately what per cent of the total number of females in the organization?
The circumference of the two circles is 198 cm and 352 cm respectively. What is the difference between their radii?
Each side of square ‘A’ is 4 cm less than that of square ‘B’. The perimeter of a rectangle is 3 times the difference of the perimeters of the tw...
The angle of elevation of the top of a tower from a point on the ground which is 45 meters. away from the foot of the tower is 30°. The height of the t...
The base of a solid right prism is a triangle whose sides are 7cm, 24cm and 25cm. the height of the prism is 5 cm then the total surface area of the pri...
The perimeter of a rectangle is given as 72 cm, and the side of a square is equal to the mean of the length and breadth of the re...
