# Combinatorics - math word problems

#### Number of problems found: 390

• A machine
A machine produces steel rods of normally distributed length; the mean length and the standard deviation being 50.0 cm and 0.5 cm respectively. The rods do not conform to safety standards if they are either shorter than 49.1 cm or longer than 50.7 cm in l
• Three subjects
In a class of 40 students, 18 passed mathematics, 19 passed accounts, 16 passed economics, 5 mathematics and accounts only, 6 mathematics only, 9 accounts only, 2 accounts and economics only, if each student offered at least one of the subjects. a) how ma
• Hockey Championships
At the 2021 World Hockey Championships, there are eight teams in Group A, each of which plays seven matches. There are 4 points for each team to gain points (3-2-1-0), but it is always paired with the opponent's points ( 0-1-2-3). How many points are ther
If there are 3 roads from town A to town B And 4 roads from town B to town C, in how many ways can one go from town A to town C and back to town A, through town B, without passing through the same road twice?
• In PE
In PE, students play a game where they do different exercises depending on the color of marble that Coach Forbes draws. Coach Forbes has a jar with 6 red marbles, 12 blue marbles, 16 purple marbles, 2 green marbles, and 4 yellow marbles. What is the proba
• Poisson distribution - daisies
The meadow behind FLD was divided into 100 equally large parts. Subsequently, it was found that there were no daisies in ten of these parts. Estimate the total number of daisies in the meadow. Assume that daisies are randomly distributed in the meadow.
• Right key
The hostel has 4 rooms. The keys to each room are not numbered. Each of the four guests took one key. What is the probability that everyone took the right key?
• 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?
• Smoker male
For a person selected randomly from a certain population, events A and B are defined as follows. A = event the person is male B = event the person is a smoker. For this particular population, it is found that P(A ) = 0.53, P(B) = 0.15, and P(A n B ) = 0.1
• Five number code
I have a 5 digit code on the bag that I forgot. All I remember is that it was a symmetric number and the sum of its digits was 22. Write all the numbers that can be a code. .

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