A few math problems, help me solve them by tonight! 1. Xiao Ming goes shopping in the shop. Here is a dialogue between him and the aunt of the salesgirl Xiao Ming said, "I'll buy three of these toothpastes and five of these toothbrushes." The aunt of the salesman said, "it's 15 yuan and 60 cents in all." After payment, Xiaoming said: "Auntie, I don't want this toothpaste. Let's change a toothbrush." The aunt of the salesman said, "I'll give you 2 yuan back." Can you work out the unit price of toothpaste and toothbrush from their conversation?

A few math problems, help me solve them by tonight! 1. Xiao Ming goes shopping in the shop. Here is a dialogue between him and the aunt of the salesgirl Xiao Ming said, "I'll buy three of these toothpastes and five of these toothbrushes." The aunt of the salesman said, "it's 15 yuan and 60 cents in all." After payment, Xiaoming said: "Auntie, I don't want this toothpaste. Let's change a toothbrush." The aunt of the salesman said, "I'll give you 2 yuan back." Can you work out the unit price of toothpaste and toothbrush from their conversation?

Set X Yuan for toothbrush and Y yuan for toothpaste, then there will be
5X+3Y=15.6
6X + 2Y = 13.6, you can find it

1. A cylindrical glass is filled with water. The height of the water surface is 2.5 cm, and the bottom area of the inner side of the glass is 72 square cm. After putting a 6 cm square iron block into the glass, the water surface does not submerge the iron block. At this time, the height of the water surface is () cm
2. A cylindrical container containing water has a bottom inner radius of 5 cm, a depth of 20 cm and a water depth of 15 cm. Now, an iron cylinder with a bottom radius of 2 cm and a height of 17 cm is vertically put into the container. At this time, the water depth of the container is () cm
3. A cylindrical cup with a bottom radius of 10 cm is filled with some water. A conical plumb with a bottom radius of 5 cm is put into the water. The water surface rises by 0.5 cm, and the height of the cone is () cm

1. 5 cm. Let the water surface be x cm. The volume of iron under the water surface is 6 * 6 * X. the volume of water is 72 * 2.5. Now the volume of iron under the water + the volume of water is 72 * x 36x = 72x-72 * 2.5. The solution is x = 52

The distance between the two cities is 405 km. A bus and a truck start from the two cities at the same time and run in opposite directions. The bus runs 44 km per hour and meets four hours later. How many km per hour does the truck travel?

(405 - 44 * 4) △ 4 = 57.25 (km / h)