1.
Let A be the set of all students of a boys school. Show that the relation R in A
given by R = {(a, b): a is sister of b} is the empty relation and
R' = {(a, b) : the difference between heights of a and b is less than 3 meters) is
the universal relation.

Masons cell phone company charges $0.12 for every text message he sends plus $2.50 per month if mason sent 25 messages this month how much money does he owe the one with the correct answer and explanation gets 10 points and is marked as the brainliest answer