Answer:
Since x=20, y=60
We have 20 1-dollar coins and 60 50-cent coins
Step-by-step explanation:
Let the number of 1-dollar coins =x
Let the number of 50-cent coins =y
Mrs.Sanders had 80 coins
Therefore: x+y=80 ......(i)
The total amount added up to $50
Therefore: 1x+0.50y=50 .........(ii)
From equation (i), x=80-y
Substituting x=80-y into equation (ii)
1x+0.50y=50
80-y+0.50y=50
80-50=y-0.5y
30=0.5y
y=30/0.5=60
From (i)
x+y=80
x+60=80
x=80-60=20
x=20, y=60