Is the following format of answer accepted in I.C.S.E?????

Asked by Nachiket Muley | 9th Jan, 2014, 09:21: PM

Expert Answer:

Your answer is very short and for marking scheme you need to write steps to solve the above question.
 
If this question is coming in any competitive exams, then you will get full marks. But for boards(any), you need to write the solution in steps.
 
Solution:
 
Given that pocket money of Ravi and Sanjeev are in the ratio 5:7
 
Therefore, 5x and 7x are the pocket money of Ravi Sanjeev, where x is the constant of proportion.
 
Given that expenditure of Ravi and Sanjeev are in the ratio 3:5
 
Therefore, 3y and 5y are the expenditure of Ravi Sanjeev, where y is the constant of proportion.
 
Also, given that both the persons save Rs.80
 
Therefore, we have,
 
5x - 3y = 80....(1)
 
7x - 5y = 80....(2)
 
Multiply the equation (1) by 5 and equation (2) by 5, we have
 
25x - 15y = 400...(3)
 
21x - 15y = 240...(4)
 
Subtracting equations (3) from (4), we have
 
4x = 160
 
That is x = 40;
 
Thus, the pocket money of Ravi and Sanjeev are 5x and 7x =
 

Answered by Vimala Ramamurthy | 10th Jan, 2014, 10:34: AM

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