Math practice for 13 year olds - page 3 of 428
Number of problems found: 8556
- A train 6
A train covers distances of 10 km, 20 km, and 30 km at speeds of 50 km/h, 60 km/h, and 90 km/h respectively. Find the average speed of the train in km/h. - The surface 5
The surface area of a cylinder is 6,140 cm², and the base radius is 25 cm. What is the height? - A building
A building is 125 metres tall and 80 metres long. On a scale drawing, the height of the building is 25 centimetres. What is the length of the building on the scale drawing in centimetres? - A watch
If a watch is sold for $60, there is a loss of 15%. At what price must the watch be sold to make a profit of 2%? - A rope for cow
Find the length of rope by which a cow must be tethered so that it can graze an area of 154 m². - The average 19
The average age of a class was 15 years. When 5 boys with an average age of 12 years and 6 months were admitted, the class average decreased by 6 months. How many students were in the class originally? - The Earth and Moon
The diameter of the Moon is approximately 1/4 of the diameter of the Earth. What fraction of the Earth's volume is the Moon's volume? - The shadow 2
The shadow of a tower standing on level ground is found to be 40 m longer when the Sun's altitude is 30° than when it is 60°. Find the height of the tower. - Journey trip
A man performs 2/15 of his total journey by rail, 9/20 by bus, and the remaining 10 km by bicycle. What is the total length of his journey? - Salaries - ratio3
The salaries of A, B, and C are in the ratio 2:3:5. If their salaries are increased by 15%, 10%, and 20% respectively, what will be the new ratio of their salaries? - Goods train
A goods train runs at a speed of 72 km/h and crosses a 250 m long platform in 26 seconds. What is the length of the goods train? - Fabric - Jose
Jose had 1 5/7 yards of fabric and used 24/59 of a yard for a project. What fraction of the fabric did he use? - Beeps
An electronic device beeps after every 60 seconds. Another device beeps after every 62 seconds. They beeped together at 10 a.m. When is the next time they will beep together? - Angle over circle
In the figure, O is the centre of the circle and AB is tangent to the circle at B. If angle OAB is 28°, find angle AOB. The figure is not to scale. - Angle of inclination
Find the angle of inclination of a ramp that rises 80 cm over a horizontal length of 200 cm. - Submarine and plane
A submarine is floating 900 m below sea level. Directly above it, an aeroplane is flying at an altitude of 4,800 m above sea level. What is the vertical distance between the two? - The average age The average age of a 5-member committee is the same as it was 3 years ago, because an old member has been replaced by a new one. Find the difference between the ages of the old and new members.
- Digits sum
A two-digit number is 3 times the sum of its digits. If 45 is added to the number, its digits are interchanged. Find the sum of the digits of the number. - Salary up and down
After reducing a man's salary by 50%, it is then increased by 50%. Find the net gain or loss percentage. - Division with a remainder
Find the smallest number which, when divided by 8, 12, and 20, leaves a remainder of 5 in each case.
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