1 A bag contains 100 marbles. Some are red and the rest are black. There
are 3 red marbles for every 1 black marble. How many red marbles are in
the bag?

there are 33 marbles

Step-by-step explanation:

100÷3

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so:

b. b < 1 might be the correct answer