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標題:

MATHS``

發問:

• 求助，等比數列，急！！！
• 續百分法（複利息）
• Permutation and Combiniation

• 求助，等比數列，急！！！
• 續百分法（複利息）
• Permutation and Combiniation

 

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There are 42 students in F.1A.The number of boys is 1/3 more than of girls.Find the numbers of boys and girls respectively. 我唔識計牙.. 唔該大家幫幫手啦!!! (用代數式)

最佳解答:

Let x be the number of girls in F.1A then, (1+1/3)x = 4x/3 is the number of boys in F.1A x + 4x/3 = 42 (Total number of students in F.1A) 7x/3 = 42 x/3 = 6 x = 18 So, there are 18 girls in F.1A. Also, there are: 4(18/3) = 24 boys in F.1A

其他解答:

Assume number of girls is X. then the number of boys is (1+1/3)X So, X + (1+1/3)X = 42 X = 18 = girl number (1+1/3)*18 = 24 = boys number|||||Let a be the number of the girls. 4/3a+a=42 7/3a=42 a=18 The number of the girls is 18. The number of the boys. 18+18x1/3 =24 The number of the boys is 24.|||||let there are y girls and y(1+1/3) boys in the class y + y(1+1/3) = 42 y + y(4/3) = 42 (7/3)y = 42 y = 18 18 girls 18(1+1/3) = 24 boys