On a number line, a number, b, is located the same distance from 0 as another number, a, but in the opposite direction. the number b varies directly with the number a for example b -2 3/4 when a= -2 3/4which equation represents this direct variation between a and b?

i think it’s a i believe

you would 18 *0.25 = 4.5

in counting the number of heads in 4 coin flips, the probability that we get exactly one head is the probability that we get anyone of the following 4 outcomes: httt, thtt, ttht, or ttth. each has probability 1/16, so the probability to get exactly one head in 4 flips is 1/16 + 1/16 + 1/16 + 1/16 = 4/16 = 1/4.