30÷(5-3)×(5+3)= 120 (page 1)
2. For a project, Party A works for 2 days, then Party B works for 3 days to complete 1/5 of the project, and then Party A and Party B cooperate for 5 days to complete 2/5 of the project. How many days will Party A have to do the rest?
The sum of work efficiency of both parties is: 2/5÷5=2/25.
The working efficiency of B is: 1/5-2×2/25= 1/25.
The working efficiency of A is: 2/25- 1/25= 1/25.
The remaining A needs to be done: (1-1/5-2/5) ÷1/25 =10 (days).
There are 462 students in a school, and 2/3 girls are equal to 4/5 boys. How many boys are less than girls?
Two thirds of girls are equal to four fifths of boys.
The ratio of girls to boys is 4/5: 2/3 = 6: 5.
The number of girls is 6 and the number of boys is 5.
There are fewer boys than girls 1.
1 copy: 462÷(6+5)=42 (person)
There are 42 fewer boys than girls.
Aunt Li bought 560 clay dolls, and 70 of them were damaged. If he wants to make a profit of 5%, what percentage of the purchase price must he sell?
Let the buying price be "1" and the selling price be x.
(560-70)x =( 1+5%)× 1×560
490x= 1.05×560
7x=8.4
x= 1.2
1.2÷ 1× 100%= 120%
Answer: It must be sold at 20% of the purchase price.
5. Grade 6 students in a primary school 19 1, selected from boys 1/9 and1/girls participated in the competition. The ratio of the remaining boys to girls is 4: 3. How many boys and girls are there in the sixth grade?
There are x boys and (19 1-x) girls in grade six.
( 1- 1/9)x:( 19 1-x- 1 1)= 4:3
3(8/9)x=4( 180-x)
(8/3)x=720-4x
(20/3)x=720
x= 108
191-108 = 83 (person)
A: Grade 6 boys 108, girls 83.