Question 177878
Let the amount of dimes be d, then the amount of quarters are 3d
Let the amount of half-dollars be h
Then d + 3d + h = 70, or 4d  +  h  =  70
Then d(.10) + 3d(.25) + h(.5)  =  17.75, or .1d  + .75d  +  .5h  =  17.75, or .85d  +  .5h  =  17.75


					  4d   +     h   =   70 -----------(i)
				    	.85d   +   .5h   =   17.75 -------(ii)
Multiply eq. (i) by - .5	      -2.00d   -   .5h   =   -   35 -------(iii)
Add eq (ii) & (iii)			     -1.15d      =   -   17.25     
						   d     =      15

				     4(15)   +      h   =   70
				          60   +   h    =   70
		    	                          h     =     10
Therefore, there are 15 dimes - $1.50
       there are 45 quarters - $11.25
    there are 10 half-dollars - $5.00