Math practice for 13 year olds - page 85 of 434
Number of problems found: 8667
- Home is home
At 65km/h, Alfred can reach home in 50 minutes. At what speed should he drive his car so that he can reach home 10 minutes earlier?
- Reciprocal 13
What is the product of 5 2/3 and its reciprocal?
- Residents
In a college dormitory, 1/10 of the residents are juniors, and 2/5 of the residents are sophomores. What fraction of the students at the dormitory are juniors and sophomores?
- Musa worked
Musa worked for 44 hours during one five days a week. His hours are from Monday through Thursday: 3 3/4, 6 7/12, 11 5/16, and 6 5/6. Calculate the number of hours he worked on Friday.
- Quotient of two fractions
If the quotient of 8/9 and 1/3 is subtracted from the product of 2 3/4 and 1 3/5, what is the difference? Write the solution as a mixed number or a fraction in the lowest terms.
- For what
For what value of x is -5x+8=-6 a true statement? Write your answer as a decimal.
- Chessboard 80533
How many ways can one white and one black square be selected on an 8x8 chessboard if the selected squares cannot lie in the same row or column?
- Kilograms 80532
75 kg of flour is ground from 100 kilograms of wheat. How much wheat is needed to obtain 135 kg of flour?
- Twenty-five 80531
People must collect twenty-five tons of waste paper to save 160 trees. How many kilograms of paper must be collected to save 32 trees?
- Cake 9
1/3 of a cake costs 3$ and 50 cents. Then how much does the whole cake cost?
- Shani
Shani mixed 1 1/3 cups peanuts, 1 3/4 cups raisins, and 1 1/2 cups chocolate chips to make a trail mix. How many cups of trail mix did she make? Responses
- Osmium wire
A spiral of osmium wire has a resistance of 300 ohms at a temperature of 20 degrees Celsius. To what temperature was the coil heated if its resistance rose to 2940 ohms? (alpha=4*10-3 1/K)
- Coefficient 80516
An aluminum wire has a resistance of 4.25 ohms at 0 degrees. Determine its resistance at a temperature of 200 degrees Celsius. The temperature coefficient of the electrical resistance of aluminum is 4.4·10-3 1/K.
- Coefficient 80515
A tractor pulls a tree trunk weighing 1.5 t for a distance of 2 km along a horizontal road at a constant speed. What mechanical work does it do if the coefficient of sliding friction is 0.6?
- Coefficient 80514
The resistance of a platinum wire at a temperature of 20°C is 20 Ω, and when heated to 500°C, it increases to 59 Ω. Determine the mean temperature coefficient of platinum
- Temperature 80513
A copper wire coil winding has a resistance of 10 Ω at a temperature of 14°C. The passing current by the coil heats up, and its resistance increases to 12.2 Ω. To what temperature did the coil winding heat up? α = 3.92 * 10-3 1/K.
- Two tariffs
You pay $20 and $0.05 per minute, and somebody else spends $15 and $0.25 per minute. How long would it take for both of you to spend the same amount?
- Centimeters to inches
How many inches are there in 70.32 centimeters when 1 inch equals 2.54 centimeters? Round off your answer to the nearest thousandth place.
- Calculate: 80496
Calculate: |7 − 15| + |8| − |−13| − 1 =
- Six-fifteenths 80487
Hermione Granger prepares an anti-boredom potion. She read in the recipe that the brew volume is two-ninths of liquid toad poison, six-fifteenths of mandrake nectar, and the rest is 34 milliliters of water. How many milliliters of Potion will Hermione mak
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