3 out of 1-25 minus 3 out of 4

3 out of 1-25 minus 3 out of 4

It's 13 out of 100

1 + 1 / 4 minus 3 / 4 =? How to calculate

Simple calculation: 3 / 1-4 + 1 / 4
=1 / 4 + 1 / 4
=1 / 2

Is the efficiency of workers proportional to the number of participants and the time required? Why?

First of all, we should be clear about what is work efficiency, that is, the ratio of achievements to time, energy, money, etc. when carrying out a certain task. Therefore, work efficiency is a ratio. Before we say that a certain is proportional to a certain, we should first ensure that a certain quantity remains unchanged before we can say what the ratio is

Simple calculation method of 19 + 199 + 1999 + 19999

Every two people who attended a party shook hands once. All of them shook hands ten times. How many people attended the party? Needless to say, how to conceive? The more detailed the reason, the easier it is to understand. I won't be able to avoid similar problems next time

In order not to repeat, we number everyone
Suppose there are n people in all
The first person shakes hands with everyone else, so he shakes n n-1 times
The second man shook hands with the rest, so he shook hands n-2 more times
……
After that, everyone shakes hands with the rest, one less time for each
To the penultimate person, he only had the last person to shake hands, so he shook hands again
So the total number of handshakes is 1 + 2 + 3 + +(n-1)
Because 10 = 1 + 2 + 3 + 4
So 4 = n-1
n=5
So there were five people in all

19,23,26,29,28,32,34,35,41,33,31,25,27,31,36,37,24,31,29,26,30 find their median and mode

The 21 data are arranged from small to large
19,23,24,25,26,26,27,28,29,29
thirty
31,31,31,32,33,34,35,36,37,41
Obviously, the middle number (11th number) is 30
The largest number is: 31
So they have a median of 30 and a mode of 31

If x = 2Y = 1 and x = 1y = 2 are two sets of solutions of the equation MX + NY = 3, find the values of M and n

Substituting x = 2Y = 1 and x = 1y = 2 into MX + NY = 3, we get 2m + n = 3M + 2n = 3 (3 points), and the solution is m = 1, n = 1. (5 points)

Negative 81 ／ 2 and 1 / 4 × (4 / 9) ／ (16) =?

Negative 81 ÷ 2 and 1 / 4 × (4 / 9) ÷ (16)
=-81x4/9x(-4/9)x(-1/16)
=-16x1/16
=-1

To make up a linear equation of one variable so that the solution of the equation is 1, we must go through the past denominator process

X/2*40=20

(999 / 1000) * (1 / 100) + (111 / 1000) * (27 / 100) simple calculation!

999/1000x1/100+111/1000x27/100
=999/1000x1/100+111/1000x9x3/100
=999/1000x(1/100+3/100)
=999/1000x1/25
=999/25000