Why was this amendment necessary?

a. many states established districts where only members of some
ethnicities could vote.

b. poll taxes and literacy tests made it too complicated for many
african americans in the south to vote.

c. african americans who were former slaves were not considered
american citizens.

d. despite their citizenship, african americans were legally prohibited
from voting in some states

Aswimming pool has an input pump for filling the pool and an output pump for emptying the pool. the input pump can fill the pool in 3 hours, and the output pump can drain the pool in 5 hours. as you go to bed, the pool is full, but a neighbor’s kid turns on the output pump. at midnight, you awake to find the pool half empty. immediately, you turn on the input pump, but you are sleepy and forget to turn off the output pump. at what time will the pool become full?

The number of nails of a given length is normally distributed with a mean length of 5.00 in, and a standard deviation of 0.03 in. find the number of nails in a bag of 120 that are less than 4.94 in. long.

Awater tank holds 18000 gallons. how long will it take for the water level to reach 6000 gallons if the water is used at anaverage rate of 450 gallons per day