Math practice for 13 year olds - page 130 of 428

Number of problems found: 8558

A turtle 2
A turtle can walk 1/12 of a kilometer in an hour. The turtle is 1/5 of a kilometer away from a pond. How long will it take the turtle to reach the pond at this speed?
Cylinder cube percentage
Calculate the percentage of the cube volume that represents the volume of the cylinder inscribed in the cube. The cylinder's bases are circles inscribed on two opposite walls of the cube with an edge a = 14 cm.
Two companies
The two companies did work together for 100 days. The first company would do it in 150 days. How many days would the work take the second company?
Resistor voltage current
A current of 5 mA flows through a resistor with an electrical resistance of 600 Ω. What electrical voltage do we measure between the resistor terminals?
Voltage - Kirchoff laws
At a voltage of 2.5V, a current I1= 20mA flows through the resistor. What will the voltage be at the resistor's ends when the current I2= 1,2A passes through it?
Prism - right isosceles
Find the volume and surface of a prism with a height of 120 mm. Its base is a right isosceles triangle with a leg length of 5 cm.
Eva brigade earnings
Eva received money for a brigade. She saved three-fifths of the money, lent one-quarter to her sister, and bought a T-shirt for the remaining 180 CZK. How much CZK did Eva earn on the brigade?
Sphere volume formula
If V=4/3 π r³, find the value of V when r = 7, the value of r when V=113 1/7
Bronze
How much tin is in 3.6 kg of bronze if it contains 15%?
Trapezoid angle construction
Sestroj trapezoid ABCD, if a = 8cm, b = 5cm, alpha = 60 °, beta = 75 °
Manganese
Manganese bronze contains the following metals per pound: copper 0.89 lb, tin 0.10 lb, and manganese 0.01 lb. How much copper is in a shaft that weighs 235 pounds?
Face combinations
If I have 20 sets of eyes, 20 noses, and 20 months, how many unique face combinations can I make?
The diagonals
The diagonals in the diamond ABCD are 6 cm and 8 cm long. What is the perimeter of this diamond?
Trapezoid floor slats
The room has a trapezoidal floor plan; we need to polish it. The parallel sides in a trapezoid are 4,800 mm and 4,400 mm long, and the oblique sides are 4,600 mm and 5,100 mm long. There are two 900 mm wide doors in the room. One strip measures 250 cm and
Multiple ratio
The numbers of boy students, girl students, teachers, and other staff of the school are in the ratio of 14:12:2:1. How many teachers are there at school if there are 216 girl students at school?
Plants
The number of germinated plants increased by 50% to 300 from morning to evening. How many plants germinated in the morning?
Figure set probability
The set contains 12 different figures. How many unidentified individual figures do I have to buy to have precisely two complete sets with a 90% probability after unpacking them?
The ladder
The ladder makes an angle of 2°30' with the wall and reaches a height of 2.3 m. How far is the ladder from the wall?
Plot exchange area
Mr. Nový exchanged his rectangular plot of 5.2 hectares with his neighbor for two. The first plot has the shape of a square with a side of 70 m, and the second has the shape of a rectangle with dimensions of 110 m and 410 m. After the exchange, does the n
After the discount
The dishwasher costs 210 EUR after the discount. How much did it cost before the discount if the new price is 90% of the original price?

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