A model a car is 150000 yuan per car, B model car is 100000 yuan per car, a model a car can make 8 & nbsp; 000 yuan, and a model B car can make 5 & nbsp; 000 yuan. A company bought 30 models a and B cars with 4 million yuan, and the total profit is no less than 204000 yuan after all of them were sold? How many ten thousand yuan are the profits of these schemes?

A model a car is 150000 yuan per car, B model car is 100000 yuan per car, a model a car can make 8 & nbsp; 000 yuan, and a model B car can make 5 & nbsp; 000 yuan. A company bought 30 models a and B cars with 4 million yuan, and the total profit is no less than 204000 yuan after all of them were sold? How many ten thousand yuan are the profits of these schemes?

Suppose we buy a car of type A, then we buy a car of type B (30-a). According to the meaning of the question, we get 15A + 10 (30 − a) ≤ 4000.8a + 0.5 (30 − a) ≥ 20.4. Solving this inequality, we get 18 ≤ a ≤ 20. ∵ a is an integer, ∵ a = 18, 19, 20. ∵ there are three schemes to buy cars

Can the formula 1-cos (x) 3 = log2 1 / 10 hold for a math problem

log2 1/10
=-log2(10)
log2(10)>log2(8)=3
-log2(10)4
So it doesn't work

Add conditions or questions according to the formula
1、 There are 120 peach trees in the orchard______ ）How many pear trees are there______ ）(2) 120x (1 + 1 / 5) condition: (_______ ）(3) 120x (1-1 / 5) condition: (uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuy) There are 375 story books in the library, and the number of science and technology books is 6 / 7 of story books_______ ?（1）357x6/7 （______） （2）357x（1-6/7） （______） （3）357x（1+6/7） （______）

(1) Condition: (pear tree is 1 / 5 of peach tree) (2) condition: (pear tree is 1 / 5 more than peach tree) (3) condition: (pear tree is 1 / 5 less than peach tree)
(1) Question: (how many science and technology books are there?) (2) question: (how many more story books are there than science and technology books?) (3) question: (how many story books and science and technology books are there altogether?)
If you have any questions, just ask me directly~

Denote X in the following formulas by the formula containing y
（1）y=lg x/(x+1)
（2）y= (e^x-1)/(e^x+1)

(1)
y=lg x/(x+1)
x/(x+1)=10^y
x=(x+1) * 10^y
x(1-10^y)=10^y
x=10^y/(1-10^y)
(2)
y= (e^x-1)/(e^x+1)
(e^x-1)=y*(e^x+1)
e^x -1 = ye^x + y
e^x(1-y) = y + 1
e^x = (1+y)/(1-y)
x = ln((1+y)/(1-y))
(end)