SOLUTION: A lady has only Rs. 1 and Rs.2 coin in her purse. If in all she has 50 coins totalling Rs. 70, Find the number of coins of each type.

Algebra ->  Finance -> SOLUTION: A lady has only Rs. 1 and Rs.2 coin in her purse. If in all she has 50 coins totalling Rs. 70, Find the number of coins of each type.       Log On


   

Question 977753: A lady has only Rs. 1 and Rs.2 coin in her purse. If in all she has 50 coins totalling Rs. 70, Find the number of coins of each type.
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
Let the number of Rs. 1's be x
Then the number of Rs. 2's, using
ONE PART = TOTAL MINUS OTHER PART,
is Rs. 50-x.
                      Value      Value
Type       Number       of         of
 of          of        EACH       ALL
coin        coins      coin      coins
-------------------------------------------
Rs. 1         x         1         1x
Rs. 2       50-x        2       2(50-x)
-------------------------------------------
TOTALS      50      -----         70

 The equation comes from the column on the right

  %28matrix%284%2C1%2CValue%2Cof%2CALL%2C%22Rs.+1%27s%22%29%29%22%22%2B%22%22%28matrix%284%2C1%2CValue%2Cof%2CALL%2C%22Rs.+2%27s%22%29%29%22%22=%22%22%28matrix%285%2C1%2CTotal%2Cvalue%2Cof%2CALL%2Ccoins%29%29

1x + 2(50-x) = 70
 x + 2(50-x) = 70
  x + 100-2x = 70
    -x + 100 = 70
          -x = -30
           x = 30 = the number of Rs. 1s.

The number of Rs. 2s is 50-x or 50-30 or 20 Rs. 2's.

Checking:  30 Rs. 1's is 30 Rs. and 20 Rs. 2's is 40 Rs.
            That's 50 coins.
            And indeed 30 Rs. + 40 Rs. = 70 Rs.
Edwin