A bag contains 120 marbles. Some are red and the rest are black. There are 19 red marbles for every black marble. How many red marbles are in the bag?

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.

Polynomials plz quick 1: subtract and simplify (–y^2 – 4y – 8) – (–4y^2 – 6y + 3)

Fawn bought a total of 70 cakes for a tea party. she spent $3,025. fawn bought vanilla cakes for $22 each and a fruit filled cake for $55 each. the system of equations below can be used to find the number of vanilla cakes, v, and the number of fruit filled cakes, f, fawn purchased. which system of equations has the same solution as the system below.