Math practice for 13 year olds - page 74 of 422

Number of problems found: 8424

Resistor 81502
How big a series resistor do we need to connect to the LED if a voltage drop of 3.2 V is to be created on it and a current of 16 mA flows through the diode? We want to connect the diode to a voltage of 5V.
Selection 4
Selection triangle, which is similar to the given triangle RTG. ∆ RTG, r= 24 dm, t = 28 dm, g= 30 dm. ∆ SHV= 6 dm, h= 7.5 dm, v= 7 dm ∆ VSH= v= 7 dm, s= 6 dm, h= 7.5 dm ∆ HVS= h= 7.5 dm, v= 7 dm, s = 6 dm. ∆ VHS= v= 7 dm, h = 7.5 dm, s= 6 dm. ∆ HSV= h= 7.
Horsepower 81496
The electric motor has an efficiency of 80% (power and input ratio). What is the power input of this motor if its power is 5 horsepower (HP)? Enter the result in kilowatts (kW) and round to one decimal place (1 HP = 3/4 kW).
Three-day trip
George went on a moped for a three-day trip. He drove 90 km on the first day, 30 km on the second day, and 60 km on the third day. He always drove at the same average speed and always the whole number of hours. Calculate the average speed if George drove
Threefold 81491
Find a number whose fivefold is 8 greater than threefold.
Triangle 81484
Choose a triangle that is similar to the given triangle. - ∆ TFC= t= 8 cm, f= 9 cm, c= 7 cm. : ∆ PKU= p= 45 cm, k= 35 cm, u= 40 cm. ∆ UPK= u= 40 cm, p= 45 cm, k= 35 cm. ∆ PUK= p= 45 cm, u= 40 cm, k= 35 cm. ∆ KPU= k= 35 cm, p= 45 cm, u= 40 cm. ∆ KUP= k= 35
Indistinguishable 81481
How many ways can a tower of five yellow and four blue cubes be built so that each yellow cube is adjacent to at least one other yellow cube? Yellow dice are indistinguishable, and so are blue dice.
Triangles 81480
Decide whether the triangles are similar. Choose between Yes/No. ∆ YUO: y= 9m, u= 17 m, o= 12 m, ∆ ZXV= z= 207 dm, x= 341 dm, v= 394 dm
Fifteenths 81479
Little Aja planned to read the book, which has 120 pages, for 4 days. On the first day, she read a quarter of the whole book; on the second day, she had training and therefore only read two-fifteenths of the book; on the third day, she read seven-twentiet
Archaeologists 81478
Archaeologists need to find out the size of the vessel if the sherd found was in the shape of a circular section with a length of 12 cm and a height of 3 cm. What is the area of this section?
Quadrilateral calc
The square ABCD is given. The midpoint of AB is E, the midpoint of BC is F, CD is G, and the midpoint of DA is H. Join AF, BG, CH, and DE. Inside the square (approximately in the middle), the intersections of these line segments form a quadrilateral. Calc
Base and legs
A right triangle has a base/legs/length of 12 cm, and the angle with the hypotenuse is 13 degrees. What is the length of the second hypotenuse?
Identical loaves of bread
If the clerk at the buffet bought 15 identical loaves of bread, she would have 5 euros left in her wallet. If she bought 3 loaves of bread less, she would have 8.60 euros left. How many euros did she have in her wallet?
Times 81462
5 to -11 times 5 to -7/5 to zero times 5 to -15 minus ( -5 ) to -2
Intersection 81457
Two cars started from the right-angled intersection of two roads. The first at a speed of 80 km/h and the second at a speed of 60 km/h. How fast are they moving away from each other?
Neighbor 81456
Mr. Novak earns as many euros in half a year as his neighbor in 4 months. The neighbor earns 420 euros more per month than Mr. Novak. What is the monthly income of Mr. Novak?
Arithmetic 81453
A set of numbers 5,8,13,15,17,19 is given. What number should be added so that the arithmetic mean is 16?
Machine particles
Since the start of the shift, 1,260 parts have already been produced on the press. This fulfilled 3/7 (three sevenths) of the daily plan. How many parts does the press still have to produce when the plan is to be fulfilled at 105%?
Probability 81446
What is the probability that each digit is different in a five-digit number?
Square-shaped 81445
The area of the square-shaped room on the drawing with a scale of 1:150 is 6 cm square. Determine the actual area of the room in square meters.

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