Please explain these issues briefly and clearly

Set: The time for the completion of the assignment is n days.

If 300 are completed every day and 3 days in advance, then: task = 300 (n-3), if 180 are completed per day and completed 5 days later, then: task = 180 (n+5), jujube judgment.

Then, 300 (n-3) = 180 (n + 5), first approximate the number of points: 15n-45 = 9n + 45, n = (45 + 45) (15-9) = 90 6 = 15 days.

Why do you have to + 2 waiters after 3x9? Patently misleading.

Generally. Those 3 cost a total of 3x9=27 yuan.

And 27 yuan includes 25 (boss) + 2 (waiter)...

So you're 27+2 wrong.

27 is the money you spend. And the money you returned in your hand is 3 yuan.

In fact, it is still 27 + 3 = 30 yuan. Look

Those 3 cost a total of 3x9=27 yuan.

And 27 yuan includes 25+2

27 is the money you spend. And the money you returned in your hand is 3 yuan.

In fact, it is still 27 + 3 = 30 yuan.

This is a Mongolian person, this meal is only 25 The three of them gave 27 2 yuan to the waiter, how can you say 1 yuan?

1. Nature.

Interval formula complex: 1458 pure increase.

Reduction, two, three, six, seven is the size of bai.

Except for the increase of four and the decrease of five du, the rest of the four or five degrees zhi are pure intervals dao2, and the nature of the interval will change by adding the root or crown of the interval to the diacritical mark, that is, as shown in Figure 1, the law of change has been clearly shown in the diagram.

3. The basic law of transposition of intervals: the sum of intervals after transposition is 9, and the nature of intervals after transposition is opposite.

Large becomes small, small becomes large, (multiplied) increases (multiplies) decreases, (multiples) decreases (multiplies) increases, and pure remains the same.

For example, the major third degree of transposition becomes six degrees smaller, the increase of five degrees of transposition becomes four degrees, and the pure fifth degree of transposition becomes four degrees of purity, etc.

Special case: an increase octave is transposed to a minus octave. Because the crown note of an octave is lowered by an octave to increase by one degree, the position of the root note and the crown note is not converted, and it needs to be lowered by another octave to become a subtracted octave.

253 drinks = 30, 1 drink = 10

1 drink + 2 burgers = 20, each burger = 5

1 burger + 2 fries = 9, fries = 2

So 5+2x10=25