Four application problems in the first grade of junior high school

There are two kinds of ballpoint pens, one is 3 yuan and the other is 4 yuan. I want to buy 45 ballpoint pens now. Just spent1how to allocate 50 yuan?

It should be x kilometers later.

X/[2+ 18]+X/[ 18-2]= 3

X=80/3

So walk 80/3 kilometers.

Set up x cubic meters of processing table.

25x*2= 150(8-x)

x=24-3x

x=6

So it can process 6*25= 150 tables and 2* 150=300 chairs.

Processing 300 sets of tables and chairs

Wood required = 300/25+2 * 300/150 =12+4 =16 cubic meters of wood.

So we have to buy 16-8=8 cubic meters.

Let 50 students draw lots, and prepare 5 marked and marked students from the 50 lots to participate in the survey. Because of the pigeon hole principle, for each student, the paintings may be equal.