Answer:
The fraction of horses that are Morgan's=17/20
Step-by-step explanation:
Step 1: Determine fraction for each breed
Arabians=1/4
Thoroughbreds=2/5
Morgan's=unknown
Step 2: Express each breed as a fraction of the total
Number of Arabians=fraction of Arabians×total number of horses
Let total number of horses be x
Arabians=(1/4)×x=1/4 x
Thoroughbreds=(2/5)×x=2/5 x
Morgans's=m
Step 3: Calculate fraction of Morgans
Total number of horses=Arabians+Thoroughbreds+Morgans
x=(1/4)x+(2/5)x+m
solve for m;
m=x-(1/4)x-(2/5)x
m=x-3/20x
m=17/20 x
The fraction of horses that are Morgan's=17/20
