400*7/8=350 heads
350/7/ 10=500 heads
2. Wang Qiang read a science and technology book. He has read five eighths of the book, and there are ninety pages left. How many pages are there in this science book? 1-5/8=3/8
90/3/8=240 pages
3. In a charity donation activity, 24 boys in class 6/kloc-0 donated money 120 yuan, 18 girls donated money 108 yuan. What is the average class donation?
120+ 108=228 yuan
24+ 18=42
228/42=5 and 3/7
4. Party A and Party B start from two places which are100km apart and go in opposite directions. A walks 6 kilometers per hour, B walks 4 kilometers per hour, A takes the dog and the dog walks 10 kilometers per hour. The dog and A set out at the same time, met B and then turned around and walked towards A; When they meet A, they go to B … until they meet. How many kilometers did the dog walk?
When 100/(6+4)= 10
10 *10 =100km
5. The picture on the right is composed of a cube with a length of 5㎝. How many cubic centimeters is its volume? How many square centimeters is its surface area?
5*5*5= 125 volume
5*5*6= 150 surface area
6. There are 18 boys in the fifth grade science and technology group, 8 girls visit the provincial museum and 26 people stay for one night. The housing standard is: 2 people in 40 yuan, 3 people in 50 yuan and 4 people in 60 yuan. How to arrange the minimum accommodation fee? How many different accommodation schemes can you design at the lowest cost? (Want 2 kinds)
1.8/4*60= 120 yuan
18/4=4 rooms, leaving 2 people.
4*60+40=280 yuan
280+ 120=400 yuan.
Six quadruple rooms, 1 double room. 400 yuan?
Scheme 1: 8 girls live in 2 quadruple rooms, 18 boys live in 4 quadruple rooms, 1 double room.
If boys and girls can live together, in Scheme 2, 7 girls 1 boys live in 2 quadruple rooms, 17 boys 1 girls live in 4 quadruple rooms, and 1 double rooms.