A: The total purchase cost 1 and the pricing 1.5.
[(0.8* 1.5+0.2* 1.5*0.8)- 1]/ 1=44%
The number of girls in a school is 40 more than 2/5 of the whole school, and the number of boys is 1 and 1/3 times that of girls. How many students are there in this school?
Answer: The number of boys is 1 and 1/3 times that of girls, which means that the number of boys is 4/3 times that of girls.
(40+40× 1 and 1/3) ÷ (1-2/5-2/5×1and1/3)
=280/3÷ 1/ 15
= 1400 students-* * Yes 1400 students.
There are three piles of chess pieces, each pile has the same number of chess pieces, and only black and white chess pieces. The number of sunspots in the first pile is as much as the number of Bai Zi in the second pile, and the number of sunspots in the third pile accounts for 1/4 of all sunspots. Put these three piles of debris together. What percentage does the total number of Bai Zi account for in the total number of all chess pieces?
Answer:
Assuming that there are 1 sunspot in the third pile, there are 4 sunspots in the total * * *, and 3 sunspots in the first pile and the second pile * * *.
Because there are as many sunspots in the first pile as there are Bai Zi in the second pile, and there are as many chess pieces in the three piles.
In other words, there are as many albinos in the first pile as there are sunspots in the second pile.
Heap 1: 1 black, 2 white;
Heap 2: 1 white, 2 black
That is, 1 black +2 black = 1 white +2 white =3.
It is known that there are three pieces in each pile.
Heap 2: 1 black, 2 white
White characters account for (2+ 1+2)/9=5/9.
When Xiao Ming reads a book, the number of pages he has read is 2 more than 3/5 of the whole book, and the number of pages he has not read is 3/5. How many pages are there?
Answer:
Assume that the number of pages read is 1 and the number of pages unread is 3/5.
The total number of pages is 8/5.
2/[ 1-(8/5*3/5)]*8/5=80
The number of people in Class Six (1) who participate in the meteorological interest group is not the number of people who participate in the meteorological group 1/2. Later, six people joined the meteorological group, so the number of participants was 4/5 of the number of non-participants. How many people are there in this class?
Answer:
At the beginning, when the ratio of participants to non-participants is 1:2, participants account for 1/3 of the total number, and non-participants account for 2/3 of the total number.
Later, when the ratio of participants to non-participants was 4: 5, participants accounted for 4/9 of the total number, and non-participants accounted for 5/9 of the total number.
Then just look at the changes in the number of people in Batanga, and the number of participants increased by 4/9- 1/3= 1/9 of the total number.
Add 6 students, and the class size is 6÷ 1/9=54 students.
The number of red ink bottles in the school accounts for 4/9 of the total number of red and black inks. Later, I bought 60 bottles of red ink, accounting for 6/ 1 1 of the total amount of red and black ink. How many bottles of red and black ink are there in this school?
Answer:
Before buying, the proportion of red ink in the total amount is
4:9
***9 copies
After buying, the ratio of scarlet letter to total amount is
6: 1 1
*** 1 1 copy
The number of bottles of black ink remains the same, and the two extra bottles are the number of bottles of red ink.
So the total number = 60/(11-9) x11= 330.