A car from a to B, 3 hours 126km, according to the speed of 2.5 hours to reach B Come on!

A car from a to B, 3 hours 126km, according to the speed of 2.5 hours to reach B Come on!

(126/3)*(3+2.5)=236.5
two hundred and thirty-six point five
A car always runs at the same speed. It travels 216 kilometers on the first day and 126 kilometers on the second day. It takes 2 hours less on the second day than on the first day. How many hours on the second day?
(216-126)÷2
=45 km
126÷45
=2.8 hours
A highway is 336 kilometers long. A bus takes 3.2 hours to complete the whole journey, and a truck takes 3.8 hours to complete the whole journey. How fast is the speed of the bus faster than that of the truck? Relation: the speed of a passenger car is required to be faster than that of a freight car
The relationship: the speed of passenger cars - the speed of freight cars = the speed of passenger cars faster than freight cars; the speed of passenger cars faster than freight cars must be calculated first: the speed of passenger cars, the speed of freight cars, the formula is: 336 △ 3.2-336 △ 3.8 ≈ 105-88.42 = 16.58 (km)
The addition and subtraction of integral in the first grade of Mathematics
It is proved by algebraic formula that if the sum of all digits of a three digit number is a multiple of 9, then the three digit number is also a multiple of 9
Let the hundreds of the three digits be a, the tens be B, and the ones be c. then 100A + 10B + C = 99A + 9b + A + B + C = 9 (11a + b) + A + B + C9 (11a + b) is a multiple of 9. If the sum of all digits is a multiple of 9, then a + B + C is a multiple of 9, because 9 (11a + b) is a multiple of 9, and a + B + C is a multiple of 9, so 99A + 9b + A + B + C is a multiple of 9
Let a three digit number be a, C, C and a + B + C = 9K
And this three digit number can be expressed as 100A + 10B + C = 9 (11a + 9b) + A + B + C = 9 (11a + 9b + k) is a multiple of 9, then the proof of the proposition.
Example: 999
9+9+9=27 27/9=3
999/9=111
Three hundred and thirty-three
3+3+3=9 9/9=1
333/9=37
Let the order of three digits be a, B, C (1)=
A pile of 44.5 tons of coal was transported by 3.5-ton truck for 10 times, and the rest was transported by 2.5-ton truck for at least several times
（44.5-3.5×10）÷2.5
=9.5÷2.5
=3.8 times
=4 times
There are 50 students in class 61 of sunshine primary school. Eight boys and a quarter of girls are selected to take part in the sports meeting
How many boys and girls are there
Suppose there are x girls and 50-x boys
（1-1/4)x=50-x-8
x=24
Boys 26 girls 24
A and B start from a and B at the same time, and run in opposite directions. After 5 hours of meeting, B runs 180 kilometers. If the speed ratio of a and B is 5:6, how many kilometers is the distance between a and B?
A: the distance between a and B is 330 km
A problem of integral addition and subtraction
6. Read the solution to the following question and fill in the blanks
Is the polynomial P = 3 χ & sup2; - 6 χ + 7, q = a χ & sup2; + B χ + C, P + q a quadratic trinomial? If so, please explain the reason; if not, please explain what kind of algebraic formula P + Q is, and point out the conditions a, B, C should satisfy
Solution: P + q = (3 χ & sup2; - 6 χ + 7) + (a χ & sup2; + B χ + C) = (3 + a) χ & sup2; + (B-6) χ + (7 + C)
(1) When a__________ P + Q is a binomial;
(2) When a__________ ,b__________ P + Q is a linear expression;
(3) When a__________ ,b__________ P + Q is a constant;
(4) When a__________ ,b__________ ,c__________ P + Q is a quadratic trinomial
Note that all superscripts of & sup2; are 2, not Z!!!!!!
In addition, pay attention to the reasons!
1 not = - 3
2 a = - 3 B not = 6
3 a=-3 b=6
4 a not = - 3 B not = 6 C not = - 7
It takes 20 vehicles to transport a pile of coal with a load of 4 tons. How many vehicles will it take to transport a pile of coal with a load of 5 tons?
20 × 4 ／ 5 = 80 ／ 5, = 16 (vehicles), answer: 16 vehicles are needed to complete the transportation
Mineral water one yuan a bottle, two empty bottles can change a bottle of mineral water, ten yuan can drink how many bottles
18. Originally, I bought 10 bottles, then I could exchange 5 bottles with empty bottles, 2 bottles with 5 bottles, and 1 bottle with the remaining two empty bottles