Math practice for 13 year olds - page 90 of 414
Number of problems found: 8262
- Chessboard square selection
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? - Wheat flour grinding
75 kg of flour is ground from 100 kilograms of wheat. How much wheat is needed to obtain 135 kg of flour? - Paper tree saving
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) - Aluminum resistance temperature
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. - Tractor friction work
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? - Platinum temperature coefficient
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 - Coil resistance temperature
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. - Absolute value expression
Calculate: |7 − 15| + |8| − |−13| − 1 = - Potion volume preparation
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 - Wire cut 2 We can cut a length of wire into five pieces, each 24 cm long. How many pieces, each 15 cm long, can be cut from the wire?
- Glass sheet weight
What is the weight of a sheet of glass 75 cm x 120 cm and 2 mm thick if one cubic meter of glass weighs 2500 kilograms? - The grocery
Susan has decided to make grocery combos for her shop. The wholesaler she buys from sells sugar in packets of 20 in a carton, flour in packets of 12 a carton, and 15 bags of rice in a carton. How many of each item should she buy so there are an equal numb - Wire charge current
A constant current of 80 mA passes through the wire. What charge passes through the conductor in 1 h? - Source voltage resistance
Determine the source voltage to which we must connect a 1k ohm resistance wire if a current of 40 mA is to flow through it. - Bulb filament resistance
A current of 0.2 A flows through a light bulb connected to a voltage of 6 V. What is the resistance of the red-hot filament?
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