Solution: let the purchase price of goods be x yuan. Judging from the meaning of the question:
( 1+ 10%)* X = 900 * 90%-40
1. 1X=770
X=700
The purchase price of this commodity is 700 yuan.
The sum of three consecutive even numbers is 74 greater than the smallest one. What is the sum of these three consecutive even numbers?
Solution: Let the middle even number be X and the smallest even number be X-2.
(X-2)+X+(X+2)=(X-2)+74
2X=72
X=36
So the smallest even number is 36-2=34.
The sum of the number of excavators and the number of loading and unloading vehicles in a construction site is 2 1. If each excavator digs 750 cubic meters of soil every day and each loader transports 300 cubic meters of soil every day, in order to transport the soil dug every day in time, Q: How many excavators and loaders are there respectively?
Solution: Suppose there are X excavators, then there are 2 1-X loaders. Judging from the meaning of the question:
750*X=300*(2 1-X)
450X=6300
X= 14
Loader: 2 1- 14=7.
A factory originally planned to make tents in 26 days. After the work, we produced 10 more tents every day than before, and the result was completed four days ahead of schedule. How many tents were originally produced every day? How many tents are there in this batch?
Solution: Suppose that X tents can be produced every day.
26X=(26-4)*(X+ 10)
4X=220
X=55
So this batch has 55*26= 1430 tents.
The charging standard of tap water in a city is: the part that does not exceed 10 ton is charged by 2 yuan per ton, and the part that exceeds it is charged by 3 yuan per ton. If a household pays 30 yuan in May, how much water does it consume?
Solution: let's assume that the water consumption of this household is X tons.
10*2+(X- 10)*3=30
3X=40
X=40/3