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Solving Speed and Simple Interest Problems using Allegation Rule
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This lesson shows the area and scope of the mixture and alligation. Here we solve the questions of simple interest and speed distance time with the help of alligation rule.

Abhishek Kumar
UPSC Aspirant| Cleared SBI PO| Cleared BOB PO| NDA, AFCAT exam| Attended SSB thrice| Cracked SSC CHSL| Worked as Software engineer IBM

Unacademy user
Bhai koi samjhao same kaise h?
since the distances covered with the speed of 7 and 12 are not same so the ratio of time won't be directly related to ratio of speed. so here we will have to use the formula of avg speed to get the ratio of time. avg speed =[7xT1 + 12×T2]/total time. here T2 =10-T1. thus we will get the ratio of time 2:3.
If ratio of speed is 2:3 , then how come ratio of time be also 2:3 ?? And how's distance be same in both the cases? #Problem14
Speed and time inversely proportional to each other....if speed ratio ratio 2:3.time taken ration should be both have taken the same....
Can anyone explain?speed and time ration taken?

  2. ABOUT ME: oCompleted B.Tech Cleared Bank Of Baroda Cleared SSC CHSL oUPSC Aspirant oCurrently working in IBM India o Email- bitus 1 oFollow: 1424

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  4. PROBLEM 12 A person has Rs. 5000. He invests a part of it at 3% per annum and the remainder at 8% per annum simple interest. His total income in 3 years is Rs. 750. Find the sum invested at different rates of interest. Soln: Since total interest in 3 years is Rs 750 So avg rate of interest= (100*750)/(5000*3)= 5% 2 So, investment at 3% is (3/575000-3000 And investment at 8% is (2/575000-2000

  5. PROBLEM 13: A man borrows a total sum of Rs. 10,000 from two sources. To one he pays 10% and to the other 5% per annum simple interest. If the total interest paid by him every year is Rs. 700, how much did he borrow at each rate of interest? Soln: Average rate of interest= (700*100)/(10,000*1)= 7% per annum 10% 5% 7% 2 Amount borrowed at 10%=(2/5)"10,000-Rs 4000 So, amount borrowed at 5%= Rs 6000

  6. PROBLEM 14: A person covers a distance of 100 kms in 10 hours, partly by walking at 7 kms/hr and the rest by running at 12 kms/hr. Find the distance covered in each part. Soln: Avg. Speed-100/10=10 kms/hr 12 10 24 So ratio of speed is 2:3 So ratio of time is also 2:3 Time taken at 7kms/hr=(2/5/10-4 hrs. So Distance covered at 7kms/hr=7*4=28kms Hence distance covered at 12 kms/hr=100-28=72 kms


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