Fractions - 9th grade (14y) - math problems

Double ratio
The mobile phone was twice gradually discounted in the ratio of 3: 2 1 half: 5 quarters. How much did it originally cost if the price was CZK 4,200 after a double discount?
The number 72
The number 72 increase by 25%. By how much % will you have to reduce the number you created to get the number 72 again?
Adam
Adam has half the money in his right pocket than in his left pocket. If he transferred 40 crowns from the left pocket to the right, he would have the same in both pockets. Calculate how many crowns does Adam have in his left pocket more than in his right?
Half of halves
Half of the square we cut off, then half of the rest, etc. Five cuts we made in this way. What part of the content of the original square is the content of the cut part?
The angles
The angles in the triangle are in the ratio 12: 15: 9. Find the angles.
Cllub flag
The children had the club flag sewn on. The red color covered 2/20 of the total area of the flag, the blue area a fifth, the yellow 19% of the total area. What% is the green area occupied?
The four
The four pirates divided 65 coins to each other. They were sorted by age, the youngest receiving the least number of coins, each half more than the previous one. How many coins did the oldest pirate receive?
Corona again
If the population on long island is 7.75 million and the coronavirus has affected 22,178. What percent of the population is affected. (looking for 1 in? If possible)
Triangular prism
The base of the perpendicular triangular prism is a rectangular triangle with a hypotenuse of 10 cm and one leg of 8 cm. The prism height is 75% of the perimeter of the base. Calculate the volume and surface of the prism.
What percent
What percent of 51 3/5 is 47 2/5?
Discounts 2
The local fitness center offers membership discounts for hospital employees. According to the membership brochure, you will receive a discount of 25% on a membership that normally costs $65 per month. How much will you pay for an annual membership if you
Adding
Divide number 135 into two additions so that one adds 30 more than 2/5 of the other add. Write the bigger one.
Aircraft angines
The two engines of the aircraft are enough to supply the fuel for five hours of operation. However, one of the engines has a malfunction and thus consumes one-third more fuel. How long can the plane be in the air before it runs out of fuel? After an hour
Hiking trail
The newly built hiking trail leads 25% through the field, 3/8 of the trail leads through the forest and the remaining 9 km along the river. How long is the train?
3/8 off
A shirt cost 38.95 How much will you pay for the shirt if it has a discount tag for 3/8 off? Round to the nearest cent
The fastest
The fastest boat can reach speeds more than 710% as fast as the Queen Mary 2. How would you express this number as a fraction and as a decimal?
Scholarship
The annual scholarship of the best student and second-best student in the class is 3500 euros in total. The best student scholarship in 8 months is the same as the second-best student scholar in the class for the whole year. How big is the annual scholars
Trio ratio
Hans, Alena and Thomas have a total of 740 USD. Hans and Alena split in the ratio 5: 6 and Alena and Thomas in the ratio 4: 5. How much will everyone get?
Cake ingredients
The yeast cake contains milk, yeast, sugar, and flour in a ratio of 20: 4: 1: 15. What percentage of flour is in yeast?
Two companies
The family ordered two companies to modify the garden. The first would be done in 20 days, the second would take 40% less time. How long will they work together if the second company started working when the first worked for 4 days?