Math practice for 13 year olds - page 2 of 434
Number of problems found: 8665
- Angle over circle
In the figure, O is the center of the circle and AB is tangent at B. If angle OAB is 28 degrees find angle AOB. Figure is not scaled. - Angle of inclination
Find the angle of inclination of a ramp that rise for 80 cm and is 200 cm long. - Submarine and plane
A submarine is floating 900 m below the sea level. And at the opposite point, right above the submarine, an aeroplane is flying at the height of 4800 m above the sea level. What is the vertical distance between the two? - The average age
The average age of 5 members of a committee is the same as it was 3 years ago. Because an old member has been replaced by a new. Find the difference between the ages of old and new member. - 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 the salary of a man by 50%, it is increased by 50%. Find the loss or gain percent. - Division with a remainder
Find the least number which when divided by 8, 12, and 20 leaves a remainder of 5 in each case.
- Correcting mean
The average of 10 numbers is calculated as 25. It is discovered later on that while calculating the average, one number, namely 36 was wrongly read as 56. Find the correct average. - Two friends 5 Two friends, X and Y. X is 36 years old and Y is 16 years. In how many years X will be twice as old as Y?
- Subtracting 7
Subtracting 50 from 50% of a number we get 50 as remainder. Find the number. - Rhombus = area, diagonal
The area of a rhombus is 144 sq cm. One of its diagonals is twice the other. How long is the shorter diagonal? - Train station
A man walks from his house to station. If he walks at 5 km/h he misses a train by 7 minutes. However, if he walks at 6 km/h, he reaches the station 5 minutes before the departure of the train. Find the distance covered by him to reach the station. - 128 USD
128 USD is increased by 20 percentage. Determine the new amount. - Doubling - simple interest A sum becomes its double in 10 years. Find the annual rate of simple interest
- Surface = volume
If the volume and the surface area of a sphere are numerically the same then find its radius.
- The radius 4
The radius of a sphere is r=9 cm. What is the volume of this sphere? Use π ≈ 3.14 and round your answer to the nearest hundredth. cubic millimeters - Collecting money Rs 180 contained in a box of one rupee, 50 Paise and 25 Paise coins in the ratio 2:3:4. What is the number of 50 Paise coins? (One rupee = 100 paisa)
- Working group 20 men complete one-third of a piece of work in 20 days. How many more men should be employed to finish the rest of the work in 25 more days?
- 4100 USD 4100 USD was distributed in 50 boys and girls. Each boy got $ 90 and each girl $ 65. Then, find the number of boys.
- Somebody Somebody spend 5% of his wages on paying school fees. That is 800 shillings . How much does he earn?
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