1. The value of a machine depreciates every year by 10%. If its present value is rs. 38700, find its value a year ago.
  2. The salary of a bank clerk was incresed by 7%. If his present salary is rs. 8025, what was it before increment?

1) Suppose the value of machine one year ago is x.
Rate of depreciation every year = 10%
So, value of machine this year = x-x×10100 = x-x10= 9x10
And the given present value is Rs.38700, so we have;
9x10 = 38700x = 38700×109 = 43000
Therefore, the value of machine one year ago is Rs.43000.

2) Suppose the salary of bank clerk was x before increment.
Increment percentage = 7%
So, the present salary = x+x×7100 = 107x100
And the given present salary is Rs.8025, so we have;
107x100 = 8025x = 8025×100107 = 7500
Therefore the salary before increment is Rs.7500

  • 2

Answer of 1) Rs.42570

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