Math practice for 13 year olds - page 8 of 421
Number of problems found: 8405
- Consecutive odd nums
Sum of four consecutive odd numbers is 40. Find the numbers.
- Time and distance
A man walking at a speed of 4 km/h can reach a destination in 3 hours. If he increases his speed by 1 km/h, how much time will he save?
- Spheres to cone
Two solid spheres of radii 2 cm and 4 cm are melted and recast into a cone of height 8 cm. Find the radius of the cone so formed.
- A train 3
A train takes 3 hours to go from one station to another station. If its speed is decreased by 12 km/h then the journey time will increase by 45 min. What is the distance between the two stations?
- The remainder
Find the remainder if 17²00 is divided by 18.
- A contractor 2
A contractor has to complete his contract in 92 days. 234 men were set to do the work, each of them works for 16 hours/day. After 66 days, 4/7 of the work is completed. How many additional men may be employed, so that the work may be completed in time, ea
- The square - midpoints
The area of a square ABCD is 36 cm². Find the area of the square obtained by joining the midpoints of the sides of the square ABCD.
- The average 16
The average of 50 numbers is 38. If the two numbers 45 and 55 are not considered, what will be the average of remaining numbers?
- Gain or loss
A man purchases a certain number of apples at 3/eur and same number of apples at 4/euros. He mixed them together and sells them at 3/euros. What is the gain or loss percent? Write answer as number, loss as negative, gain as positive percent.
- Number of sides
Find the number of sides of a regular polygon whose each exterior angle has a measure of 45°.
- Freezing
A certain freezing process requires that room temperature be lowered from 40°C at the rate of 5°C per hour.What will be the room temperature 12 hours after the process begins?
- Time interval
Find the time interval between 7:40 AM and 1 : 20 PM.
- Angle of elevation
The angle of elevation of the top of an unfinished pillar at a point 150 m from its base is 30°. If the angle of elevation at the same point is to be 45°, then the pillar has to be raised to a height of how many meters?
- The distance 4
The distance between two towns is 120 km there are approximately 8 km in each 5 mi. Which measurement is closest to the number of miles between each two towns?
- Lemon tarts
A baker made some lemon tarts. He sold 40% of the tarts in the morning, 2/5 of the remaining tarts in the afternoon and had 54 tarts left. How many tarts did he bake altogether?
- A student 8
A student was asked to write 25 * 9² . By mistake he write 2592. Find the difference.
- Two trains 12
Two trains 128m and 132m long are running towards each other on parallel lines at 42km/h and 30km/h respectively. In what time will they clear of each other from the moment they meet?
- One combine
One combine harvester can harvest a field of corn in 4.5 hours. Another harvester can harvest the same field in 3 hrs. If the farmer uses the two harvesters at the same time. How long will it take to harvest the entire field?
- A tank 2
A tank can be filled by a pipe A in 3 hours and by pipe B in 5 hours. When the tank is full, it can be drained by pipe C in 4 hours. If the tank is initially empty and all three pipes are open, how many hours will it take to fill up the tank?
- Length measurement
Choose the measurement closest to 60 cm: ...
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