<PRE><B>Question 1016108</B>
you have 70 coins of 10 and 50 value, total value is 1900. 

I will call the 10 unit T, and 50 unit, F, in other words, T is the number of 10 units coins.

T+F=70
10T+50F=1900  

Now multiply first equation by -10 , both sides,

-10T-10F=-700
10T+50F=1900   and add the second equation

40F=1200

F=30
T=40

40*10 =400
30*50=1500

Total value 1900</PRE>