Question
A container has 40 litres of a solution which contains
25% acid. How many litres of a 50% acid solution must be added so that the resulting mixture has 40% acid?Solution
Quantity of acid in 40 L = 25% of 40 = (25/100) × 40 = 10 L Let x litres of 50% acid solution be added. Acid added = 50% of x = x/2 Total acid = 10 + x/2 Total volume = 40 + x We want 40% acid: (10 + x/2) / (40 + x) = 40/100 = 2/5 Cross multiply: 5(10 + x/2) = 2(40 + x) 50 + (5x/2) = 80 + 2x Multiply by 2 to clear fraction: 100 + 5x = 160 + 4x 5x − 4x = 160 − 100 x = 60 Answer: 60 litres of 50% solution.
The volume of a solid cube is 2744 m3. If whole cube is to be painted at a rate of Rs. 7.5 per m2, then what will be the cost of p...
If the areas of three adjacent faces of a rectangular box which meet in a corner are 12cm2, 15cm2 and 20cm2 respective...
The length of a rectangle is 7 metres more than its width. If the perimeter of the rectangle is 74 metres then what is the area (in m2Â ) of ...
The diameter of the base of a cylindrical drum is 70 cm and its height is 15 cm. The drum is full of water and the water from the drum is transferred to...
A right-angled triangle has sides 12 cm, 16 cm, and 20 cm. A circle is inscribed within this triangle. Find the radius of the inscribed circle.
Angle bisectors of Q and R meet at point S, inside the triangle PQR. If angle QSR = 120Ëš , then the measure of angle P is:
The length, breadth and height of a storeroom are 12m, 7m and 10m respectively. If each box occupies 40 m3 of space, then how many boxes can ...
A chord of the larger among two concentric circles is of length 10 cm and it is tangent to the smaller circle. What is the area (in cm²) of the annula...
A group of boys has an average weight of 44 kg. One boy weighing 50 kg leaves the group and another boy weighing 40 kg joins the group. If now the aver...
A circular garden has a radius of 14 m. A path of width 2 m is constructed all around it outside. Find the approximate area of the path. (Use π = 22/7)
Relevant for Exams:
