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The seventh grade homework 36 is the answer to P49-50.
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1.C

2.B

3.B

4.4,3

5. 145

6. (1) The rents for 60 seats and 45 seats are X and Y respectively.

x-y = 200; 4x+2y = 5000; The solution is x = 900y = 700.

(2)5x+y = 5 * 900+700 = 5200;

7. Set the starting price X and the fare per kilometer Y;

x+8 * y = 17; x+20 * y = 35; X=5,y = 1.5;

8.( 1) Let the number of men and women be x and y respectively.

x+y = 100;

0.6 * x+0.4 * y = 0.49 * 100;

The solution is x = 45y = 55.

(2) Because there are more boys than girls in B school, the excellent score rate of boys in B school is higher than that of girls in A school. ..

For example, the number of boys in school B is 90 and the number of girls is10;

The excellent rate of school B is 90 * 0.57+10 * 0.37 =100 * 0.55, that is, the excellent rate is 55%>;; 49%;

.9. Let the number of people in 10 yuan and 15 yuan be x and y respectively.

12+x+y+3 = 40; 5 * 12+ 10x+ 15y+20 * 3 = 400; X= 19,y = 6;

10. Set the number of brands A X and B Y..

In two cases (1), choose the model of brand B as D.

x+y = 36; 6000 x+5000y = 100000; X=-80,y = 1 16; unreasonable

(2) Select the model of brand B as E..

x+y = 36; 6000 x+2000y = 100000; X=7,y = 29

There are 7 A-type computers to buy immediately.

1 1 (1) bought x and y copies respectively.

x+y = 40; 5x+8y = 300-(68– 13); X=25,y = 15;

(2) For 68 yuan, x=29.3, y =10.7; Unrealistic.

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