Statistics - math problems

Number of problems found: 344

Average height
There are twice as many girls in the class as there are boys. The average height of girls is 177 cm, boys 186 cm. What is the average height of students in this class?
My father
My father cut 78 slats on the fence. The shortest of them was 97 cm long, the longer one was 102 cm long. What was the total length of the slats in cm?
Coordinates hexagon
The regular hexagon ABCDEF is given. Point A has coordinates [1; 3], and point D has coordinates [4; 7]. Calculate the sum of the coordinates of the center of its described circle.
Large family
The average age of all family members (children, mother, father, grandmother, grandfather) is 29 years. The average age of parents is 40 years, grandparents 66 years and all children are 5 years. How many children are there in this family?
The test
The test contains four questions, and there are five different answers to each of them, of which only one is correct, the others are incorrect. What is the probability that a student who does not know the answer to any question will guess the right answer
Medians in RT
The rectangular triangle ABC has a length of 10 cm and 24 cm. Points P, Q, R are the centers of the sides of this triangle. The perimeter of the PQR triangle is:
Troops
There are two leaders in the tourist group, with an average age of 30 years and several children with an average age of 10 years. The total age of the group is 12 years. How many children are in the group?
Marks at school
There are 30 students in the class. Five students in the class had a mark three triple at the end of the math certificate, and the other students had a mark of one or two. The average mark in all students' mathematics in the class at the end of the year w
Coordinates of a centroind
Let’s A = [3, 2, 0], B = [1, -2, 4] and C = [1, 1, 1] be 3 points in space. Calculate the coordinates of the centroid of △ABC (the intersection of the medians).
Corona virus
Calculate an estimate of the percentage of GDP (Gross Domestic Product) declined due to the quarantine related to the corona COVID-19 virus that lasts for 2 months, during which time the economic activity is down by 80%.
Aircraft angines
The two engines of the aircraft are enough to supply the fuel for five hours of operation. However, one of the engines has a malfunction and thus consumes one-third more fuel. How long can the plane be in the air before it runs out of fuel? After an hour
Water current
John swims upstream. After a while, he passes the bottle, from that moment he floats for 20 minutes in the same direction. He then turns around and swims back, and from the first meeting with the bottle, he sails 2 kilometers before he reaches the bottle.
Average monthly salary
A total of 10 teachers work at one small school in Moravia. The monthly salary of each is 21,500 CZK or 21,800 CZK or 22,500 CZK according to their education and age. The average monthly salary for this school's teacher is 21 850 CZK. How many teachers of
Panel house
The construction company has two groups of workers. Group A has more members than B. Panel house was insulated by group A in 10 days. They insulated the same block of flats together in 6 days. How many days would group B block insulate?
The bar chart
The bar chart shows the results of the math test. How many% of pupils achieved approximately better results than the average of the class? Diagram: 1-10 pupils, 2-4 pupils, 3-6 pupils, 4-2 pupils, 5-4 pupils. (lowest result are better)
Ball bearings
One bearing is selected from the shipment of ball bearings. It is known from previous deliveries that the inner bearing radius can be considered as a normal distribution of N (µ = 0.400, σ2 = 25.10^−6). Calculate the probability that the selected radius w
Trees avg
The worker planted 96 trees on Monday, 120 on Tuesday, and 61 trees on Wednesday. How many trees did he plant on Thursday if he averaged 105 trees per day?
Mixture of nuts
The mixture of nuts should be prepared from almonds, peanuts and cashew nuts ratio 1: 2: 3 (respectively). The price of almonds is 150 CZK/kg, the price of peanuts is 140 CZK/kg and the price of cashew nuts is 180 CZK/kg. The price of the mixture is deter
Father and sons
Father is 27, and his sons two and one years. In how many years will his sons sum up to half his age?
Before yesterday
He merchant adds a sale sign in his shop window to the showed pair of shoes in the morning: "Today by p% cheaper than yesterday. " After a while, however, he decided that the sign saying: "Today 62.5% cheaper than the day before yesterday". Determine the