2 yuan has X sets.

2X+5X+( 100-2X)* 10 = 480

7X+ 1000-20X=480

13X=520

X=40

100-40-40=20

So there are 40 in 2 yuan, 40 in 5 yuan and 20 in 10 yuan.

the second question

Suppose I read x pages on the first day, and the total number of pages is 6X.

(X+ 18+X):(4X- 18)= 3:5

Staggered multiplication

10X+90= 12X-54

2X= 144

X=72

So 6X=432

This book has 432 pages.

Fill in the blanks.

1。 The same circle has a radius of 5cm and a diameter of (10) cm.

2. A circle is a (geometric) figure on a plane.

3. A circle has a radius of 3 cm, a diameter of (6) cm and a circumference of (18.84) cm.

A circle has a circumference of 28.26 meters, a diameter of (9) cm and a radius of (4.5) cm.

The minute hand of a clock is 6 cm long, and it has gone (75.36) cm after two laps.

6。 The circumference of a circle is 12.56 cm. If a circle is drawn with a compass, the distance between its feet is (2) cm. 7. The radius of the outer circle is 3cm, and the radius of the inner circle is 2cm. The area of this circle is (15.7 )8. The sector area with a central angle of 90 degrees is (4) of the circle area (1).