# Buffet

In the school buffet were 30 children. 21 children bought sandwiches and 15 children bought lemonade. Four children did not buy anything. How many children bought lemonade and sandwiche?

**Result****Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):**

**Showing 0 comments:**

**Be the first to comment!**

#### To solve this example are needed these knowledge from mathematics:

## Next similar examples:

- Math logic

There are 20 children in the group, each two children have a different name. Alena and John are among them. How many ways can we choose 8 children to be among the selected A) was John B) was John and Alena C) at least one was Alena, John D) maximum one w - Pairs

From the five girls and four boys teachers have to choose one pair of boy and girl. A) How many such pairs of (M + F)? B) How many pairs where only boys (M + M)? C) How many are all possible pairs? - Freedom

In the city are 3/9 of women married for 3/6 men. What proportion of the townspeople is free (not married)? Express as a decimal number. - Two doctors

Doctor A will determine the correct diagnosis with a probability 86% and doctor B with a probability 87%. Calculate probability of correct diagnosis if patient is diagnosed by both doctors. - Segments

Line segments 62 cm and 2.2 dm long we divide into equal parts which lengths in centimeters is expressed integer. How many ways can we divide? - Subsets

How many are all subsets of set ?? - Camp

In a class are 26 children. During the holidays 16 children were in the camps and 14 children on holiday with their parents. Determine the minimum and maximum number of children that may have been in the camp and on holiday with their parents at the same - Classroom 3

How many children are in the classroom, where 13 children are higher than Lenka and 9 children lower than Lenka? - Chamber

In the chamber light is broken and all from it must be taken at random. Socks have four different colors. If you want to be sure of pulling at least two white socks, we have to bring them out 28 from the chamber. In order to have such certainty for the pai - Lentilka

Lentilka made 31 pancakes. 8 don't fill with anything, 14 pancakes filled with strawberry jam, 16 filled with cream cheese. a) How many Lentilka did strawberry-cream cheese pancakes? Maksik ate 4 of strawberry-cream cheese and all pure strawberry pancake - Pizza master

Master says that he can splits pizza to 16 parts by five equals straight cuts. Is it possible? - Count of roots

How many solutions has equation x. y = 7757 with two unknowns on the set of natural numbers? - Glasses

Imagine a set of students in your class (number of students: 19), who wears glasses. How much minimum and maximum element may contain this set. - Pytagoriade

Two fifth-graders teams competing in math competitions - in Mathematical Olympiad and Pytagoriade. Of the 33 students competed in at least one of the contest 22 students. Students who competed only in Pytagoriade was twice more than those who just competed - Trousers

In the class was 12 students. Nine students wearing trousers and turtleneck eight. How many students worn trousers with a turtleneck? - News

From 28 students buy magazine 10 The economist students, 10 Pravda students and 18 students don't buy any of these magazines. How many students buy both magazines? - Czech crowns

Small Petra save money. Grandfather give her 10 crowns. Petra asked his older sister let her calculate how much he has saved up. Sister told her that he has less than 30 crowns. If the sum is divided by three left one crown. If the sum is divided by the f