System of equations - practice for 14 year olds - page 62 of 65
Number of problems found: 1285
- Password
The voltage station is day changing the master password, which consists of three letters. The code generation process does not change and is based on the following procedure: The following letters (A) to (I) correspond to different numbers from 1 to 9 if - Exam average
The average of marks that have on the certificates students of 8A class in mathematics is exactly 2.45. If we did not add 1 and 3 of students Michael and Alena, who arrived a month ago, it would average exactly 2.5. Determine how many students have class - BW-BS balls
Adam has a full box of large or small balls, black or white. The ratio between large and small balls is 5:3. Within the large balls, the ratio of black to white is 1:2, and between small balls, the ratio of black to white is 1:8. What is the ratio of all- - Alloy
The first alloy is a mixture of two metals in the ratio 1:2; the second is a mixture of the same metals in the ratio 2:3. At what ratio do we have these two alloys put into the furnace to obtain a new metal alloy with a ratio of 17:27? (All three ratios c
- Rectangle - sides 3
If in the rectangle ABCD, we enlarge side a by 5 cm and decrease side b by 2 cm, the rectangle area will be reduced by 5 cm². When we decrease the length of side a by 4 cm, and at the same time we increase the length of side b by 3 cm, we increase the are - Aircrafts
Above the town, the hall tower flew the plane at a constant speed of 510 km/h, and 15 minutes later, the second plane at a speed of 703 km/h. How long and how far from the town hall will it be for aircraft to catch up? - Alcohol 2
Two types of alcohol, one 46% and second 64%, give 16 liters of 54% alcohol. How many liters of each type are in the mixture? - Scouts
The boys from the scout group traveled 5 days distance of 115 km. Every day walked 1.5 km less than the previous day. How many kilometers did scouts walk on the first day? - Division
Three siblings, Helena, Oliver, and George, split the bag with candies on merit in the ratio 6:1:4. How many candies should each get if in the bag were 88?
- The professor's birthday
Professor of mathematics had 44 birthdays. The director congratulated him. The professor asked the director: "And how old are you?" The director replied: "I'm exactly twice as many years as you were when I was old as to you today." How old is the director - Bases
The length of the bases trapezium is in ratio 4:5. The length of the midline is 15. How long are the bases of a trapezoid? - Tram
In the three-part tram went 206 passengers in front of others, 226 after others and in the middle half. How many passengers went in the tram total? - Brunette
The girls attending primary school are 30% blondes and 70% brunettes. 81% blondes and 19% brunette has blue eyes. How many girls attend school altogether if 470 girls have blue eyes? - TV commercials
For the typical one-hour prime-time television slot, the number of minutes of commercials is 3/8 of the actual program's minutes. Determine how many minutes of the program are shown in that one hour.
- Trains
From station 130 km away started passenger train and after 1.9 hours after the express train, which travels 27 km an hour more. Express train finish journey 5 minutes early. Calculate the average speed of these two trains. - Flowerbed
On the flowerbed were planted 280 flowers - pansies and crayons during the first week, wilts quarter of pansies and an eighth crayons, which is 20% of all flowers. How many pansies were planted on the flowerbed? - Three workers
Three workers, A, B, and C, have to work on a specific task. Workers A and B completed the task in 12 days, B with C for 19 days, and A with C for 24 days. How long would it take to complete the task for everyone alone? How long would it take to complete - Two runners
Two runners ran simultaneously towards each other from locations distant 21.4 km. The average speed of the first runner was 1/6 higher than the average speed of the second runner. How long should each run a 21.4 km, if you know they meet after 78 minutes? - Rectangles - sides
One side of the rectangle is 10 cm longer than a second. Shortening the longer side by 6 cm and extending the shorter by 14 cm increases the rectangle area by 130 cm². What are the dimensions of the original rectangle?
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