標題:
maths題 (equation)(要有步驟)
發問:
要有步驟 :h-1 over 2 -h+1 over 3 = 10.4j - 1 over 2 =18*Let all number is yA plant grows 3.5 cm per week, and it is now 10 cm tall. How many weeks later will the plant grow to a height of 27.5 cm ?Apples cost $12 per dozen more than oranges and $18 per dozen less thanpears. The total cost of 2 oranges... 顯示更多 要有步驟 : h-1 over 2 -h+1 over 3 = 1 0.4j - 1 over 2 =18 *Let all number is y A plant grows 3.5 cm per week, and it is now 10 cm tall. How many weeks later will the plant grow to a height of 27.5 cm ? Apples cost $12 per dozen more than oranges and $18 per dozen less thanpears. The total cost of 2 oranges and 4 apples s the same as the cost of 4 pears. Find the cost of a pear. John spends one-thrid of his money to but a toy. Then,he spends $20 for food. If he spends $37 in total. how much money does he have at the beginning? A wire of 72 cm long is bent into a rectangle. If the length of the rectangle is 19 cm, find the width of the rectangle. In a school, 50% of the girls and 280 boys wear glasses. If the number of girls wearing glasses is 2 over 7 of the number of boy, find the number of girls. Derek is 7 years younger than Frankie. Helen is three-quarters the age of Derek. Gary is 9 years older than Helen. If Gary is 24 years old, how old is Frankie thx ~
最佳解答:
(h – 1) / 2 – (h + 1) / 3 = 1 Multiply both sides by 6 3(h – 1) – 2(h + 1) = 6 3h – 3 – 2h – 2 = 6 h – 5 = 6 h = 11 (0.4j – 1) / 2 =18 0.4j – 1 = 36 0.4j = 37 j = 37/0.4 j = 92.5 A plant grows 3.5 cm per week, and it is now 10 cm tall. How many weeks later will the plant grow to a height of 27.5 cm ? Let the required weeks be y 10 + 3.5y = 27.5 3.5y = 17.5 y = 5 5 weeks later the plant will grow to a height of 27.5 cm Apples cost $12 per dozen more than oranges and $18 per dozen less than pears. The total cost of 2 oranges and 4 apples is the same as the cost of 4 pears. Find the cost of a pear. Let the cost of a pear be $y. 1 dozen of pears costs $12y 1 dozen of apples costs $(12y – 18) 1 dozen of oranges costs $[(12y – 18) – $12] = $(12y – 30) The total cost of 2 oranges and 4 apples = (12y – 30)(2/12) + (12y – 18)(4/12) = 2y – 5 + 4y – 6 = 6y – 11 = 4y 2y = 11 y = 5.5 The cost of a pear is $5.5 John spends one-third of his money to but a toy. Then,he spends $20 for food. If he spends $37 in total. How much money does he have at the beginning? Let John has $y at the beginning. y(1/3) + 20 = 37 y/3 = 17 y = 51 John has $51 at the beginning. A wire of 72 cm long is bent into a rectangle. If the length of the rectangle is 19 cm, find the width of the rectangle. Let the width be y cm Perimeter = 2(19 + y) = 72 19 + y = 36 y = 17 The width is 17 cm In a school, 50% of the girls and 280 boys wear glasses. If the number of girls wearing glasses is 2 over 7 of the number of boy, find the number of girls. Let the number of girls be y Number of girls wearing glass = (50%)y = (280)(2/7) 0.5y = 80 y = 160 There are 160 girls Derek is 7 years younger than Frankie. Helen is three-quarters the age of Derek. Gary is 9 years older than Helen. If Gary is 24 years old, how old is Frankie Let the age of Frankie be y Age of Derek = y – 7 Age of Helen = (3/4)(y – 7) Age of Gary = (3/4)(y – 7) + 9 = 24 (3/4)(y – 7) = 15 y – 7 = 15(4/3) = 20 y = 27 Derek is 27 years old.
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