1. if the life span of Diu Tiu Tiu is x years old, then according to the meaning of the question:
1/6x+ 1/ 12x+ 1/7x+5+ 1/2x+4 = x
General fractional solution, you can get:
x=84
His son is half his life, so:
84/2=4 years old
Diu Diu lived to be 84 years old, and his son lived to be 42 years old.
2. Let the number B be X, then the number A is:17.6-X. According to the meaning of the question:
1: 1 =( 17.6-x)； (x/ 10)
Solution:
x= 16，
17.6-x= 1.6
∴ A digit is 1.6, and B digit is 16.
3.
A regular triangle has three angles, a square has four angles, and a regular Pentagon has five angles, so:
When there are 1 regular triangles and 1 regular pentagons, there are 8 angles and (176-8)/4=42 squares.
When there are two regular triangles and two regular pentagons, there are 16 angles and (176- 16)/4=40 squares.
When there are three regular triangles and three regular pentagons, there are 24 angles and (176-24)/4=38 squares.
When there are four regular triangles and four regular pentagons, there are 32 angles and (176-32)/4=36 squares.
.............
When there are 2/kloc-0 regular triangles and 2/kloc-0 regular pentagons, there are 168 angles and (176- 168)/4=2 squares.
From the above, we can find that as long as the number of regular triangles is equal to the number of regular pentagons, then the rest must be regular quadrangles, so there are many possibilities mentioned above.
4.
The perimeter of the flower bed is:
l=πR= 15π
15π÷0.2≈235.62
Therefore, 235 seedlings should be prepared.
5.
Method 1:
Each child gets 1/8 watermelons, and a group has six children. So, a group of people got watermelons:
1/8 × 6 = 6/8 = 3/4
One * * * is eight groups. You need watermelons:
3/4 × 8 = 6 (piece)
And:
There are five watermelons, less than six, not enough.
Method 2:
Each child gets 1/8 watermelons, and a group has six children. So, a group of people got watermelons:
1/8 × 6 = 6/8 = 3/4
Now there are five watermelons, so let's set enough x-weights, so:
(3/4)* x = 5
Solution:
X=20/3=6 and 2/3.
So five watermelons are only enough for six groups, not enough for eight groups.
Therefore, five watermelons are not enough.
6.
2/7 ÷(4/5 + 2/3) = 2/7 ÷ 22/ 15 = 2/7 × 15/22 = 1/7 × 15/ 1 1 = 15/77
(5/27 + 5/36)÷5/9 = 5/27÷5/9 + 5/36÷5/9 = 5/27×9/5 + 5/36×9/5 = 1/3 + 1/4 = 7/ 12
138 ÷ 137/ 140 = ( 137+ 1) × 140/ 137 = 140+65438+
367× 367/368 = (368-1)× 367/368 = 367-367/368 = 366 and 1/368.
6/7 ÷ (6/28 - 6/35) =6/7 ÷ 6/28 - 6/7 ÷ 6/35 = 6/7 × 28/6 - 6/7 × 35/6 = 4 - 5 = - 1
7.
According to the meaning of the question:
92 (1+20%) = 92×1.2 =110.4 (ten thousand yuan)
So Aunt Li should have spent 1 104000 yuan on it.
8.
A:
1. The manhole cover on the road mainly plays the role of preventing objects from falling into the well. From the characteristics of the circle, we can know that the area of the circle of the same material is larger than that of the square or triangle. Under the same pressure, if the area increases, the pressure decreases, so the object can be protected from falling into the well.
2. The circular manhole cover can also increase the contact area with the well edge, and it will not fall into the well no matter how it is placed, while other manhole covers such as squares are easy to fall into the well.
9.
After a 10% discount, the price of each piece is:
2×0.9= 1.8 (yuan)
The profit at this time is:
1.8- 1.5=0.3 (yuan)
After the discount, the profit of 20 pieces is:
20×0.3=6 (yuan)
Initially, each profit was:
2- 1.5=0.5 (yuan)
The total profit is:
86-6=80 (yuan)
The number of handles sold is
80÷0.5= 160 (Ba)
* * * Purchase: 20+ 160= 180 (pieces)
So, * * * bought 180.
10.
If this kind of compensation occurs, according to the meaning of the problem, the premium this year is higher than the basic rate 1/5, and the premium this year is:
4000× (1+1/5) = 4800 (yuan)
If it does not happen, according to the meaning of the question, this year's premium is lower than the basic rate110, and this year's premium is:
4000× (1-110) = 3600 (yuan)
Dear, it's not easy to write so much, add some points!