# Examples for 7th grade (seventh)

1. Cuboid surface
Determine surface area of cuboid if its volume is 52.8 cm cubic and length of the two edges are 2 cm and 6 cm.
2. Cuboid - Vab
Find the surface of the cuboid when its volume is 52.8 cubic centimeters, and the length of its two edges is 2 centimeters and 6 centimeters.
3. Unknown number
I think the number - its sixth is 3 smaller than its third.
4. Simple equation
Solve the following simple equation: 2. (4x + 3) = 2-5. (1-x)
5. Efficiency
What is the power output of kettle 2 kW with efficiency 90%?
6. Plane II
A plane flew 50 km on a bearing 63degrees20 and the flew on a bearing 153degrees20 for 140km. Find the distance between the starting point and the ending point
7. Unknown number 11
That number increased by three equals three times itself?
8. Can
Watering can full of water weighs 10 kg. Half-full can weighs 5.5 kg. How much weigh can?
9. Trapezium bases
Find the trapezium height if a = 8 cm and c = 4 cm if its content 21 square centimeters.
10. Norm
Three workers planted 3555 seedlings of tomatoes in one dey. First worked at the standard norm, the second planted 120 seedlings more and the third 135 seedlings more than the first worker. How many seedlings were standard norm?
11. Orchard
3/5 of the trees in the orchard are apples, 1/3 are cherries and the remaining five trees are pear. How many trees are in the orchard?
12. Two machines
Performances of two machines are in a ratio of 7:12. A machine with less power produced 406 pieces of products per shift. a) How many pieces produced per shift second machine? b) How many pieces produced two machines together for five shifts?
13. Ornamental shrubs
Children committed to plant 240 ornamental shrubs. Their commitment however exceeded by 48 shrubs. Write ratio of actually planted shrubs and commitment by lowest possible integers a/b.
14. Algebrogram
Solve algebrogram: mama+anna=vari How many solutions are?
15. Bicycle gears
The toothed wheel on the bicycle pedal has 40 teeth, the wheel on the rear wheel has only 16 teeth. How many times does the rear wheel turn if the pedals rotate 50 times?
16. Gasoline
For nearly full tank of 40 liters of gasoline chauffeur paid 54 euros. How many euros it will cost to go 250 km long if the car has an average fuel consumption 7 liters per 100 kilometers?
17. Apples and pears
Mom divided 24 apples and 15 pears to children. Each child received the same number of apples and pears - same number as his siblings. How many apples (j=?) and pears (h=?) received each child?
18. Customer
A customer purchase three (3) writing pads from a store. She receive k9.70 change from a k10.00 note . How much was it's writing pad cost?
19. Cheetah
Cheetah elapse 150 m for 5 seconds, the eagle reaches speeds up to 230 km/h, dolphin swims 1.2 km per minute. Which animal is the fastest and slowest? The results write as meters per second (m/s).
20. Lcm simple
Find least common multiple of this two numbers: 140 175.

Do you have an interesting mathematical word problem that you can't solve it? Submit math problem, and we can try to solve it.

We will send a solution to your e-mail address. Solved examples are also published here. Please enter the e-mail correctly and check whether you don't have a full mailbox.

Please do not submit problems from current active competitions such as Mathematical Olympiad, correspondence seminars etc...