Math practice for 13 year olds - page 87 of 435
Number of problems found: 8682
- Arranged 80453
There are 390 trees arranged in rows in the orchard. How many rows are there if each row has the same number of trees greater than 30 and less than 40?
- The ages 2
The ages of the two persons differ by 18 years. Twelve years ago, the elder one was 4 times as old as, the younger one. The present age of the elder one is:
- Representation 80447
On the school ski trip, the team set off from hut A at 9:30 a.m. to hut B at a speed of 2 m/s. Fifteen minutes later, the instructor followed them at a speed of 3 m/s. At what time and distance from cabin A will the instructor catch up with the team? Plea
- Grazing 80444
Forty sheep graze in the meadow. There are 4 times more whites than blacks. How many white and how many black sheep are grazing in the meadow?
- Approximately 80443
The 94 m² flower bed is to be planted with begonias. An area of 2 dm² is needed for one seedling. How many grams of seeds should be sown if 1 g of seeds contains approximately 5000 seeds? Losses when growing seedlings are usually 30%.
- Average 80442
The daily need for fat for a person is 80g on average. Almonds contain 45% fat. How many grams of almonds would a person have to eat if he wanted to cover his daily need for fats by eating only almonds?
- Decrease 80441
By what percent does a cube's volume decrease if its edge length is reduced by a quarter?
- Contains 80440
Cow's milk contains an average of 3.6% fat. How many liters of milk are needed to make 250g of butter? Butter contains 82% fat.
- One-fifth 80438
By what percent does the area of a square increase if its perimeter increases by one-fifth?
- Fertilized 80437
Nitric lime contains an average of 19% nitrogen and 55% calcium oxide. How many grams of nitrogen per 1 m² if we bought a 25 kg package and thereby evenly fertilized a garden of 12 a?
- Rectangular 80436
The longer dimension of the rectangular plot was reduced by one-fifth, and the shorter dimension by 8%. By what percentage did the amount of land decrease? What is the perimeter of the fence now if the original dimensions of the fence were 60m and 25m?
- Carbohydrates 80435
Bread contains an average of 52% carbohydrates, and apples have 12% carbohydrates. How many apples weighing 220g would you have to eat to get as much carbohydrate as 150g of bread?
- Germination 80433
The germination rate of Hokkaido pumpkin seeds is 92%. The weight of 10 seeds is 1.6 g. How many plants will sprout if we sow 20 g of seeds?
- Joe spends
Joe spends 3 3/4 hours each day of the week doing his homework, but Mirabel spends only 2 hours each day of the week on hers. How long in a week does Joe spend on his homework more than Mirabel?
- The mass
The mass of a table is 6.4 kg, and the mass of a chair is 800 g. How many times is the table heavier than the chair?
- Elisa
Elisa got the following grades in five subjects: 87, 88, 89, 88, and 90. What is her average in the five subjects?
- Carates
A 5/8 karat diamond was purchased for $1200. What would a similar diamond weigh 1 karat cost?
- Proportional relationship 2
If y is proportional to x, and y=150 when x=2.4, what is the value of y when x=3.5
- The cost 8
The cost of 7/2 meters of cloth is $231/4. What is the cost of one meter of cloth?
- Cutting in the ratio
Suppose a 75 m rope is cut in the ratio of 2/3. What is the measure of the longest cut?
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