Answer:
Mortality rate is 0.5 per 1000 habitant
the number of deaths have increased (from 210 to 250)
Step-by-step explanation:
Hello
Mortality rate is the number of deaths in a specific population,usually expressed in units of deaths per 1,000 individuals per year

where
S=Mortality rate
D=deaths
P= population
n= is a conversion form ,such as multiplying by 10^{3}=1000, to get mortality rate per 1,000 individuals( we will use n=3)
step 1
asign
S=unknown
D=250
P=500000
n=3, (for each 1000 people)
step 2
Replace

Mortality rate is 0.5 per 1000 habitant
step 3
what if S=0.42
S=0.42(assuming it is 0.42 per 1000,n=3)
D=unknown
P=500000

the number of deaths have increased (from 210 to 250)
Have a great day