On a average day a horse might drink 50 la sheep might drink 4 l and a chicken might drink 200ml how much water would a farm with 3 horses 15 sheep and 12 chickens need for a day

Horse- 50l
sheep-4l
chicken-200ml

first you have to convert all the symbols into one, so we'll convert liters into milliliters,
 
1000ml=1l

horse= 50 ×1000=50000ml
sheep=4×1000=4000ml
chicken= 200ml

so now we have to multiply them by the number of animals,

h=50000ml×3=150000ml
s=4000×15=60000ml
c=200×12=2400ml

now add them together,

150000+60000+2400=212400ml

convert it into litres, 
212400÷1000=212.4l

answer= 212.4 l