Why is a singular verb "is" used after "One-third of the population" while a plural verb "live" is used after "70 percent of the population"? [duplicate]

1) One-third of the population of sub-Saharan Africa is undernourished.

2) Nearly 70 percent of the population still live in the countryside.

3) One-third of the residents live below the poverty level.

Why is a singular verb "is" used after "One-third of the population" while a plural verb "live" is used after "70 percent of the population"?

Why is a singular verb "is" used after "One-third of the population" while a plural verb "live" is used after "One-third of the residents"?

Solution 1:

The earlier answer by dz420 seems to have identified the reason for the difference, which I shall only try to explain in a little more detail, and illustrate with a few examples.

Words like 'X percentage' or 'one third' indicate proportion in your examples and are unlikely to influence the verb form to be used, which depends on the principal noun in each case such as 'population', 'residents' etc.

(1) Since 'residents' is obviously a plural noun, the plural form of the verb is used:

One-third of the residents live below the poverty level.

33.33 percent (one third) of the residents live below the poverty level.

(2) However, collective nouns like population, government, parliament, committee, etc are slightly more complex in that they are usually treated as singular in American English and even in Indian English (which follows the pattern of British English in most other cases), as in

The committee meets every Wednesday

Parliament is now in session

10 percent of the population wants special insurance coverage

One-third of the population of sub-Saharan Africa is undernourished

but the same (type of) words may be treated as singular or plural in British English, and the plural form is more often seen, as in

The government recommend this course of action

Nearly 70 percent of the population still live in the countryside.

Solution 2:

The word population is a collective noun that can take either a singular or plural verb, depending on the intention of the author. The intention in the first sentence is to indicate population as a single group and in the second sentence as individuals.