The total price of a mobile and a watch is rs8000.

Question

If 10% discount and 10% VAT IS imposed on both, their selling price becomes rs7920, find the marked price of mobile and watch separately.
Well I did this question and every time I get to a point where the variable are completely eliminated. The answer in the book is printed
Rs5000 and Rs 3000 but no matter what value you give to MP the condition is satisfied. Please help

Answer 1

first equation:
m + w = 8000

after discount, price would be .9(8000) = 7200
after VAT, price = 1.1(7200) = 7920

Since I got the final answer without knowing how much the watch or mobile cost, it doesn't matter how much the individual costs.

You solution is correct, you can use any cost of the two, as long as they add up to 8000

To get the actual costs of 5000 and 3000, they should have given some extra condition, such as the mobile costs rs1000 less than twice the cost of the watch.
Did you miss something in the typing?

If you didn't, the answer in the book is one of an infinite number of possible solutions.

Answer 2

Na! I checked out twice. Nothing extra is given. So it is perhaps one of those types!