Answer:
398 deaths were caused by Alzheimer.
Step-by-step explanation:
Proportionate mortality rate (PMR) gives the proportion of deaths in a given population over a period of time, this can be linked to various causes.
Mathematically PMR is reoresented below;
PMR =
X 100
where
= No. of death from a specific cause (In our case Alzheimier )
= Total No. of death at a given period
from the question the parameters were given except the number of death from Alzheimier
1.87 =
multiply both side by 21,270 to isolate

= 1.87 x 21,270
Divide both side by 100 to obtain

=

= 397.749
since dead people can not be divided