Selling item in 2 parts with given profit% or loss% (2)
Duration: 10 min
This video lesson is available to enrolled students.
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This educational video presents a lecture on solving mixture and alligation problems, a common topic in quantitative aptitude. The instructor, Yash Jain, begins by introducing the topic with a title slide. The core of the video consists of two worked examples. The first problem involves a 96 kg quantity of wheat sold in two parts at 6% and 38% profit, with an average profit of 28%. The instructor uses the alligation method, visually calculating the ratio of the two parts as 10:22, which simplifies to 5:11, and then finds the individual quantities. The second problem features a farmer selling 120 kg of corn, with good corn at a 21% profit and bad corn at a 3% loss, resulting in an overall 12% profit. The instructor again applies the alligation method, determining the ratio of good to bad corn as 15:9, which simplifies to 5:3, and calculates the respective weights. The video concludes with a 'Thanks for Watching' screen.
Chapters
0:00 – 2:00 00:00-02:00
The video opens with an animated title card for 'MIXTURES & ALLIGATIONS' by Yash Jain, a Knowledge Gate Educator. The instructor, visible in a small window, introduces the topic. The first slide, titled 'SELLING AN ITEM IN 2 PARTS WITH GIVEN PROFIT OR LOSS %', sets the context for the lesson. The instructor explains that the video will cover problems where a total quantity is sold in parts at different profit or loss percentages, and the overall average profit or loss is given, requiring the calculation of the quantities of each part.
2:00 – 5:00 02:00-05:00
The first problem is presented on screen: 'Part of 96 kg of wheat was sold at 6% profit and the other part at 38% profit. If the average profit was 28%, find the quantity sold at two profit percents.' The instructor begins the solution using the alligation method. He writes the two profit percentages (6% and 38%) and the average (28%) on the board. He calculates the differences: 38 - 28 = 10 and 28 - 6 = 22, establishing the ratio of the two parts as 10:22, which he simplifies to 5:11. He then uses the total weight of 96 kg to find the quantity sold at 6% profit as (5/16) * 96 = 30 kg.
5:00 – 10:00 05:00-10:00
The instructor moves to the second problem: 'A farmer sold 120 kg corn in two parts. Good ones were sold at a profit of 21% and bad ones were sold at a loss of 3%. On the whole he received a profit of 12%. Find the amount of good corn & bad corn?' He applies the alligation method again. He writes the profit (21%), loss (-3%), and average profit (12%) on the board. He calculates the differences: 12 - (-3) = 15 and 21 - 12 = 9, establishing the ratio of good to bad corn as 15:9, which simplifies to 5:3. Using the total weight of 120 kg, he calculates the amount of good corn as (5/8) * 120 = 75 kg and bad corn as (3/8) * 120 = 45 kg.
10:00 – 10:07 10:00-10:07
The video concludes with a final screen displaying the text 'THANKS FOR WATCHING' in white letters against a dark, gradient background. This is the end of the lecture, summarizing the completion of the two example problems.
The video provides a clear, step-by-step demonstration of the alligation method for solving mixture problems. It begins by establishing the context of selling a total quantity in parts with different profit/loss rates. The core teaching method is the application of the alligation rule, which involves finding the ratio of the parts by calculating the differences between the individual rates and the average rate. This ratio is then used with the total quantity to find the individual amounts. The two examples, one with a positive average profit and another with a mix of profit and loss, effectively illustrate the versatility of the method. The instructor's visual annotations on the digital board are crucial for understanding the calculations.