Math practice for 13 year olds - page 345 of 362
Number of problems found: 7234
- Pharmacy
At the pharmacy are in one container 20% solution in the second 50% solution of disinfectant. They need to prepare 4 L of the 48-percent solution. What amount of solution from each container is needed to mix?
- Addends
The number 681 is divided into two addends. The first was 9 greater than 60% of the second. Determine these addends.
- Typing course
Before taking a typing course, Terrence could type 39 words per minute. By the course's end, he could type 68 words per minute. Find the percent increase.
- Enrollment
The enrollment at a local college increased 8% from 9339 over last year. Find the increase in enrollment (x1) and the current enrollment (x2).
- Arm
Calculate the length of the arm r of isosceles triangle ABC, with base |AB| = 14 cm and a height v=18 cm.
- Diagonal
Calculate the diagonal length of the rectangle ABCD with sides a = 8 cm, b = 7 cm.
- Similarity
Rectangle ABCD has dimensions of 7 cm and 6 cm. Rectangle PQRS has dimensions 14 cm and 12 cm. Determine the coefficient of the similarity k of the rectangles; if they aren't similar, enter zero as the coefficient of similarity.
- Workers
Two workers, A and B, will be done work together for 10 days. They worked together for 8 days. Then A worker became ill, and worker B finished the job alone for 6 days. If every worker worked alone, how many days did the whole work take for workers A and
- Trough
How many liters of water per second can go via trough, which has a cross-section of a semicircle with a radius of 0.5 m and a water speed of 142 cm per second?
- Madams
During spring cleaning, ladies were going to wash the windows. Mother takes 5 hours to wash all the windows, the grandmother takes 3 times longer, and Paula washes all the windows in 2 hours. How many hours will you spend washing the windows of this "wome
- Gon functions
Decide which numbers (values of trigonometric functions) are positive or negative (or zero). Positive mark +1 and negative -1.
- Car
The car goes from point A to point B at speed 84 km/h and back 67 km/h. If it goes there and back at speed 77 km/h trip would take 20 minutes shorter. What is the distance between points A and B?
- Cars plates
How many different license plates can a country have since they use 3 letters followed by 3 digits?
- Lock
A combination lock will open when the right choice of 3 numbers (from 1 to 16 inclusive) is selected. A. How many different lock combinations are possible? B. Is the combination lock named appropriately?
- Train
A passenger train traveled for 2 hours 74 km. 3.1 hours after its departure started fast train and caught it on 186 km. How many km/h is different from its average speed?
- Quadrant II
Calculate the radius of the quadrant, which area is equal to the area of the circle with radius r = 15 cm.
- Coin and die
Flip a coin and then roll a six-sided die. How many possible combinations are there?
- Words
How many 2 letters "words" are possible using 14 letters of the alphabet? a) without repetition b) with repetition
- Inheritance
After death, the father (♱ 54) remained the mother (his wife) and 5 children. Inheritance by law is that the first mother will automatically get half of the property and the other half inherited by heirs, the mother and her 5 children by the same share. C
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