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我想問下以下幾題ge數學題，亦請回答ge人show 埋個step，詳細1d ...麻煩哂！1)In the formula 1/f= 1/u+1/v, if u=4 and v=2, find the value of f.2)The perimeter of a rectangle is p=2a+2b. a) If a=3, b=5 ,find the value p.b) If p=16, b=3, find the value of a.3)The weight of an empty box and a book are 2kg and 3kg... 顯示更多 我想問下以下幾題ge數學題，亦請回答ge人show 埋個step，詳細1d ...麻煩哂！ 1) In the formula 1/f= 1/u+1/v, if u=4 and v=2, find the value of f. 2) The perimeter of a rectangle is p=2a+2b. a) If a=3, b=5 ,find the value p. b) If p=16, b=3, find the value of a. 3) The weight of an empty box and a book are 2kg and 3kg respectively. If the total weight of books and a box does notexceed 60kg, find the maximum number of books inside the box. 4) Find the values of the unknowns in the following questions. a) 3p+4=0.6p+28 b) 7g-(9g-16)=14-(19-g) 5) Solve the equation of the following questions. a) x/3-x/2+1=0 b) z/2-z/6=2 6) A, B, C have a total of 60kg rice. If A has one third of the rive of B and Bhas 5 times as much as C. Find the amount of rice each person has. 7) Ina computer shop, the total income of MP3 of Brand J and Brand S is $18880. If the number of Brand S has sold was 8 and the selling price of each MP3 of Brand J and Brand S were $1280 and$1560 respectively. How many MP3 of Brand J did the shop sell ? a) use x to construct an equation and find the value of x. 8) Among 320 oranges, 12 turn bad. What is the percentage loss 詳細d丫唔該
最佳解答:
1.In the formula 1/f= 1/u+1/v, if u=4 and v=2, find the value of f. 1/f=1/u+1/v 1/f=1/4+1/2 1/f=1/4+2/4 1/f=3/4 3/3f=3/4 3f=4 f=4/3 2.The perimeter of a rectangle is p=2a+2b. a) If a=3, b=5 ,find the value p. b) If p=16, b=3, find the value of a. a) p=2a+2b p=2x3+2x5 p=16 b) p=2a+2b 16=2a+2x3 16=2a+6 a=5 3)The weight of an empty box and a book are 2kg and 3kg respectively. If the total weight of books and a box does not exceed 60kg, find the maximum number of books inside the box. The required number = (60-2)/3 =58/3 =19.33 ~19 4. Find the values of the unknowns in the following questions. a) 3p+4=0.6p+28 b) 7g-(9g-16)=14-(19-g) a) 3p+4=0.6p+28 3p-0.6p=28-4 2.4p=24 p=10 b) 7g-(9g-16)=14-(19-g) 7g-9g+16=14-19+g -2g+16=-5+g 16+5=g+2g 21=3g g=7 5) Solve the equation of the following questions. a) x/3-x/2+1=0 b) z/2-z/6=2 a) x/3-x/2+1=0 2x/6-3x/6+1=0 1=0-2x/6+3x/6 1=x/6 x=6 b) z/2-z/6=2 3z/6-z/6=2 2z/6=2 2z=12 z=6 7)In a computer shop, the total income of MP3 of Brand J and Brand S is $18880. If the number of Brand S has sold was 8 and the selling price of each MP3 of Brand J and Brand S were $1280 and$1560 respectively. How many MP3 of Brand J did the shop sell ? a) use x to construct an equation and find the value of x. Let x be the number of MP3 of Brand J that the shop has sold 1280x+1560x8=18880 1280x+12480=18880 x=5 ∴The required number =5 8)Among 320 oranges, 12 turn bad. What is the percentage loss The required percentage =12/320 x100% =3.75%
其他解答:
1. 6 In the formula, u=4 and v=2, that means, 1/f = 1/4+1/2, so f=4+2=6 2a. 16 2b. 5 Similar to Q.1. In 2a, a=3, b=5, so p=2x3+2x5, and p=6+10=16. 2b, same thing, p=16, b=3, therefore, 16=2a+2x3, so a=5. 3. 19 There is a box to hold the books. So, 60-2=58kg. (There is 58kg left) The books are 3kg per book. 58÷3=19...1. Therefore, the answer is 19. 4a. 3p+4=0.6p+28, 3p-0.6p=28-4, 2.4p=24, p=10 4b. 7g-(9g-16)=14-(19-g), 7g-9g+16=14-19+g, 7g-9g-g=14-19-16, -3g=-21, 3g=21, g=7 (P.S. 負負得正) 5a. x/3-x/2+1=0, x/3-x/2=-1, 2x/6-3x/6=-1 (6 is the common factor of 3 and 2), -x/6=-1, -x=-6, x=6 5b. z/2-z/6=2, 3z/6-z/6=2 (12 is the common factor of 2 and 6), 2z/6=2, 2z=12, z=6 Sorry, gotta go, I'll answer if I have time ok? Hope these can help you. =)4E350C6F06A145F0
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