7 skipping ropes and 10 badminton rackets * * 108 yuan, so 49 skipping ropes and 70 badminton rackets *** 108 * 7 = 756 yuan.
9 skipping ropes and 7 badminton rackets ***92 yuan, 90 skipping ropes and 70 badminton rackets ***920 yuan.
therefore
(90-49) Skipping rope is (920-756) yuan.
4 1 jump rope 164 yuan.
Each skipping rope 164/4 1=4 yuan.
Seven skipping ropes 7*4=28 yuan.
10 badminton racket 108-28=80 yuan.
Each 10 badminton racket 80/ 10=8 yuan.
Every skipping rope 4 yuan, every badminton racket 8 yuan.
2.4 cows and 9 sheep eat 63kg of vegetables a day, 1 1 cows and 26 sheep eat 177kg of vegetables a day. If a cow eats three times as much as a sheep, how many kilograms of grass does a sheep eat a day?
A cow eats three times as much as a sheep.
Then the number of kilograms eaten by four cows is equal to the number of kilograms eaten by 12 sheep.
Four cows and nine sheep eat 63 kilograms of green vegetables every day.
It is equivalent to (12+9)=2 1 sheep eating 63 kg of vegetables a day.
So a sheep ate grass one day.
=63/2 1
=3 kg
3. Two kinds of trucks are used to transport sand, three big trucks and five small trucks transport 33 tons of sand a day, and then eight big trucks and 14 small trucks transport 90 tons of sand a day. If each big truck carries twice as much sand as the small truck, how many tons of sand can each small truck carry a day?
Each big truck carries twice as much sand as the small truck.
Then that sediment transport capacity of each big truck is equivalent to that of six small truck,
Three big trucks and five small trucks transport 33 tons of sand every day.
It is equivalent to (6+5) small trucks carrying 33 tons of sand a day.
1 1 The pickup truck transports 33 tons of sand a day.
Small trucks transport 33/ 1 1=3 tons of sand a day.
4. There are 5 packages of science and technology books on the first floor, 4 packages of story books on the second floor, and 440 books of two kinds. If you change the books on the first floor and the second floor into a package, the number of books on each floor is equal. How many books are there in each package of science books and story books?
Change the books on the first floor and the second floor into a bag.
Then there are 4 packages of popular science books and 1 story books on the first floor, and 1 story books and 3 packages on the second floor.
At this time, the number of books on each floor is equal.
That is, the total number of 4 packs of science books and 1 packs of story books is equal to the total number of 1 packs of science books and 3 packs of story books.
So the total number of 3 packs of science books is equal to the total number of 2 packs of story books.
So the total number of 6 packs of science books is equal to the total number of 4 packs of story books.
It is known that the total number of 5 packs of science and technology books plus 4 packs of story books is 440.
in other words
6+5= 1 1 The total number of scientific books in the package is 440.
therefore
There are 440/ 1 1=40 science and technology books in each package.
There are 40*5=200 books in 5 packs of science and technology books.
Four packages contain 440-200=240 story books.
therefore
Each package contains 240/4=60 story books.
therefore
There are 40 science books and 60 story books in each package.