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數學題(英文)

發問:

1)In a class of 60 students, 15% of them are absent today.Find thenumber of students who are present.2)Sam bought a MP3 player for $1000. One week later ,he sold it to his brother at 95% of the original price .How much is the new price cheaper than the original price?3)If 20 x (1+ r%) = 26 , find... 顯示更多 1)In a class of 60 students, 15% of them are absent today.Find the number of students who are present. 2)Sam bought a MP3 player for $1000. One week later ,he sold it to his brother at 95% of the original price .How much is the new price cheaper than the original price? 3)If 20 x (1+ r%) = 26 , find r. 4)If 30 x (1-r%) =28.2 , find r. 5)The height of a small tree is h cm . One month later , its height increases by 28% to 44.8 cm , find the value of h . 6)The depth of water in a pool is d cm. If the depth of water decreases by 35% and becomes 1.82 m , find the value of d . 7)The following is the expenditure of a family in a certain month : $1800 on transportation , $2500 on food, $1700 on others. Express the expenditure on transportation as a percentage of that month's expenditure.

最佳解答:

1)In a class of 60 students, 15% of them are absent today.Find the number of students who are present. The number of students who are absent = 60x15%=9 The number of students who are present = total students - number of students who are absent = 60-9=51 ------------------ 2)Sam bought a MP3 player for $1000. One week later ,he sold it to his brother at 95% of the original price .How much is the new price cheaper than the original price? 1000-1000x95% =$50 ----------------- 3)If 20 x (1+ r%) = 26 , find r. 20 x (1+ r%) = 26 1+ r% = 26/20 r=30 ----------------- 4)If 30 x (1-r%) =28.2 , find r. 30 x (1-r%) =28.2 1-r% =28.2/30 r=6 ------------------ 5)The height of a small tree is h cm . One month later , its height increases by 28% to 44.8 cm , find the value of h . h(1+28%)=44.8 h=35cm ------------------- 6)The depth of water in a pool is d cm. If the depth of water decreases by 35% and becomes 1.82 m , find the value of d . d(1-35%)=1.82 h=2.8m ------------------ 7)The following is the expenditure of a family in a certain month : $1800 on transportation , $2500 on food, $1700 on others. Express the expenditure on transportation as a percentage of that month's expenditure. Month's expenditure = 1800+2500+1700=6000 & of expenditure on transportation to month's expenditure =1800/6000 x100% =30%

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