Chess pieces

There are 5 black chess pieces in the box. How many white pieces should we add to this box so that the probability of pulling out a black piece is 1: 4?

Correct answer:

x =  15

Step-by-step explanation:

5/(5+x)=1:4  5=1/4 (5+x)  x=15=15

Did you find an error or inaccuracy? Feel free to write us. Thank you!


Tips to related online calculators
Do you have a linear equation or system of equations and looking for its solution? Or do you have a quadratic equation?
Would you like to compute count of combinations?

You need to know the following knowledge to solve this word math problem:

Related math problems and questions:

  • White and black balls
    balls_bw There are 7 white and 3 black balls in an opaque pocket. The balls are the same size. a) Randomly pull out one ball. What is the probability that it will be white? We pull out one ball, see what color it is and return it to the pocket. Then we pull out th
  • Components
    components In the box are 8 white, 4 blue and 2 red components. What is the probability that we pull one white, one blue and one red component without returning?
  • BW-BS balls
    balls Adam has a full box of balls that are large or small, black or white. Ratio of large and small balls is 5:3. Within the large balls the ratio of the black to white is 1:2 and between small balls the ratio of the black to white is 1:8 What is the ratio of
  • Balls
    spheres The urn is 8 white and 6 black balls. We pull 4 randomly balls. What is the probability that among them will be two white?
  • Red balls
    gule In the bag there are 3 red, 12 blue and 8 green balls. How many red balls we must be attached to the bag if we want the probability of pulling out the red balls was 20%?
  • A box
    balls2 A box contains 6 red balls, 5 blue, and 4 white balls. Find the probability of drawing a) red ball b) non-white ball.
  • Chess
    sachovnica How many ways can select 4 fields on a classic chessboard with 64 fields so that fields don't have the same color?
  • Ace
    ace From complete sets of playing cards (32 cards), we pulled out one card. What is the probability of pulling the ace?
  • Five letters
    charH How many ways can five letters be arranged?
  • Combinations of sweaters
    sveter I have 4 sweaters two are white, 1 red and 1 green. How many ways can this done?
  • Phone numbers
    old_phone How many 7-digit telephone numbers can be compiled from the digits 0,1,2,..,8,9 that no digit is repeated?
  • Study results
    vysvedcenie There are 7 students in the class with excellent results, 6 praiseworthy, 5 good, 4 sufficient, and 3 insufficient students. What is the probability that it will be a good student when summoned?
  • We roll
    dices2 We roll two dice A. - what is the probability that the sum of the falling numbers is at most 4 B. - is at least 10 C. - is divisible by 5?
  • Roads
    mapa There are four roads from city A to city B. There are five roads from city B to city C. How many different routes can we take from city A to city C via city B?
  • Probability - tickets
    zreby What is the probability when you have 25 tickets in 5000 that you not wins the first (one) prize?
  • Soaps
    mydlo Each box has the same number of soaps. A quarter of all boxes contain only white soaps, and in each of the remaining 120 boxes there are always half the white soaps and half the green. White soaps total 1200. (a) the number of all soap boxes; (b) the smal
  • Salami
    salama How many ways can we choose 5 pcs of salami if we have 6 types of salami for 10 pieces and one type for 4 pieces?