SOLVE
1) 30Kg of a mixture of 1st and 2nd quality tea contains10Kg of second quality tea. How many 10kg of second quality tea must be added to this mixture to make it a 50% mixture?
2) The number of students of Bloom Public School increased this year by 7%. If the actual increase of students is 140,what was the original strength?
3) Nikhil invested Rs 8000 each in two banks. One bank gave him 10% simple interest. The other bank gave CI at 10% per annum. He kept the money in the banks for 3 years. Find the difference in interest between CI and SI at the end of 3 years?
4) Two trains leave a town at the same time and travel in opposite directions at the rate of 40km/h and 50km/h. In how many hours will they be 360 km apart?
5) The unit digit of number is twice the tens digit. If 27 is added to the original number, the result will be the same as the number obtained when the digits are reversed. Fined the original number.
6) By selling a house for Rs 18 lakh, Santosh lost 10% of his investment. What was his investment on the house?

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Answers

2015-01-02T17:50:56+05:30

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1.  Amount of 1st grade quality tea in the mixture = 30 - 10 = 20 kg.
     Amount to be added = X kg.
        Ratio of 2nd grade tea in the mixture = (10+X) / (30+X) = 50/100 = 1/2
                   2(10 + X) = 30 + X
                    X = 10 kg
2. 
   Original strength = N
       Increase in strength = 7 % ie., N * 7/100 = 140   
                   N = 2, 000

3)
      accumulated total in case of SI =  P +  P * r t
               = Rs 8,000 + Rs 8, 000 * 10/100 * 3 = Rs 10, 400
     accumulated amount in case of CI = P (1 + r)^n 
          = Rs 8, 000 ( 1.10)^3 = Rs 10, 648
 
  Difference between CI & SI = Rs 10, 648 - Rs 10, 400 = Rs 248

4)
    relative speed of the two trains with respect to each other = 50 + 40 = 90 kmph
     in other words, the  distance between them in 1 hour = 50+40 = 90 km
 
         duration in which they will be 360 km apart = 360 km / 90 kmph = 4 hours

5)
    number  =  a b     and         b = 2  a
         27 + 10 a + b = 10 b + a 
          a = 3   and b = 6

6)  
         Selling price = Rs 18 lakhs
         Cost price = Rs C lakhs 
           Loss % =   (C  - 18) / C * 100 = 10 
                       C = 20 Lakhs

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