There are 80 students.

x/40-x/3/40-2x/3/80= 1.5

x/40-x/ 120-x/ 120 = 1.5

x/ 120= 1.5

x= 180

* * * Making small national flag 180 noodles

Set * * * to make the X-plane school flag:

It was originally planned to make 40 noodles a day, so the production was originally planned to be completed within (X/40) days.

Half of the students take part in the production at the rate of 40 noodles a day.

When the whole class participates in the production, the speed is 80 noodles a day.

X/40-3/2=(X/3)/40+(X*2/3)/80

X/40-3/2=X/60

X/ 120=3/2

X= 180

Answer: * * * Make 180 school flag.

Solution: Suppose a * * * wants to be an X flag.

So the original planned number of days is x/40.

Because half the students eat 40 noodles every day, and the whole class eats 40*2=80 noodles every day.

Because 40 noodles are made every day, x/3 is completed and it takes x/3/40=x/ 120 days.

So the remaining 2/3x completion days are 2x/3/80=x/ 120 days.

So it actually took x/ 120+x/ 120 days.

Because it is actually one and a half days ahead of schedule, the equation is feasible.

x/ 120+x/ 120+ 1.5 = x/40

Multiply both sides by 120:2x+ 180 = 3x.

x= 180

So the column equation is 2x/3/80+x/3/40+ 1.5=x/40.

A: Make a 180 flag.

Then use one-dimensional linear equation to solve.

Solution: Assuming that the original plan takes X days to complete, the general sign should be 40x.

The first 1/3 is completed by half of the students, and the second 2/3 is completed by the whole class.

Then the flags made every day are twice as big as before, that is, 80 flags.

So there is

80(2/3

x- 1.5)=40x×2/3

The solution is x=4.5.

The total number of flags is 40x=40×4.5= 180.