# Algebra - problems - page 87

1. Cuboid The sum of the lengths of the three edges of the cuboid that originate from one vertex is 210 cm. Edge length ratio is 7: 5: 3. Calculate the length of the edges.
2. Our house Our house would paint four painters in 14 days. How long could it paint five painters? How long will it take if two other painters will come to help after 5 days?
3. Cube edges The sum of the lengths of the cube edges is 42 cm. Calculate the surface of the cube.
4. Birthday Mother bought 21 desserts on the occasion of Mirka's birthday one tips was 9 CZK and the kremlin cost 12 CZK. For all desserts, she paid 213 CZK. How many kremlins and how many tips mums did buy?
5. Cube edges If the edge length of the cube increases by 50%, how does the volume of this cube increase?
6. Pupil age I am a pupil of the primary school, I spent 1/4 of my age on the exercise of parents with children, 1/3 on drawing, 1/6 on flute. I did not have a ring for the first three years of my life and never went to two rings at once. How old am I?
7. Exponential equation Determine the value of having y in the expression (3^y): (4^-1)=36.Y is a natural number greater than zero.
8. Two diggers Two diggers should dig a ditch. If each of them worked just one-third of the time that the other digger needs, they'd dig up a 13/18 ditch together. Find the ratio of the performance of this two diggers.
9. Bicycle gear The pedal bicycle wheel has 56 teeth and a rear 20 gear tooth. How many times does the bicycle wheel turn when you make 20 turns of the pedal wheel?
10. Harvesters The first harvester will harvest the grain from the field in 20 hours, the second, the more powerful in 10 hours. How long will take harvest this field by both harvesters, if the second harvester has to be set up first and this takes 2 hours? The first har
11. Quadrangular pyramid The regular quadrangular pyramid has a base length of 6 cm and a side edge length of 9 centimeters. Calculate its volume and surface area.
12. Eggs 3400 eggs sliced hens for February and March. We have to calculate how many hens can make 3400 eggs when one hen give 2 eggs a day for 59 days.
13. Body diagonal - cube Calculate the surface and cube volume with body diagonal 15 cm long.
14. Simple equation Solve the following simple equation: 2. (4x + 3) = 2-5. (1-x)
15. PIN code PIN on Michael credit card is a four-digit number. Michael told this to his friend: • It is a prime number - that is, a number greater than 1, which is only divisible by number one and by itself. • The first digit is larger than the second. • The second.
16. Six terms Find the first six terms of the sequence a1 = -3, an = 2 * an-1
17. Fractions Three-quarters of an unknown number are 4/5. What is 5/6 of this unknown number?
18. Four numbers The first number is 50% second, the second number is 40% third, the third number is 20% of the fourth. The sum is 396. What are the numbers?
19. Regular prism The regular four-sided prism has a base of 25 cm2 and a surface of 210 cm2. Find its volume.
20. Digits How many odd four-digit numbers can we create from digits: 0, 3,5,6,7?

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