1.Mrs chan used $60 to buy some mangoes. If the price of each mango is increased by $1 she will buy 2 mangoes less with $60 . Find the original price of each mango
2.mr chan distributes 120 cups evenly into a certain number of boxes . If 3 fewer boxes are used , each boyx has to contain 2 more cups .how many boxes are there originally?
3. The area of an isosceles right -angled triangle is x/2 cm^2 . If the base increased by 2 cm and height is decrease d by 1 cm, the area of new triangle is 14 cm^2. Find x
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作者: HermionePct 時間: 2016-8-11 10:32 AM 標題: Question 1 solution
Let x be the original price of the mangoes.
Let y be the original amount of mangoes.
xy=60---(i)
(x+1)(y-2)=60---(ii)
In (i),
xy=60
y=60/x---(iii)
Sub (iii) into (ii)
(x+1)(60/x-2)=60
x=5 or -6(rejected)
Therefore, the original price of each mango is $5. 作者: HermionePct 時間: 2016-8-11 10:38 AM 標題: Question 2 solution
Let x be the original number of boxes used.
Let y be the original no of cups one box contains.
xy=120---(i)
(x-3)(y+2)=120---(ii)
In (i),
xy=120
y=120/x---(iii)
Sub (iii) into (ii)
(x-3)(120/x+2)=120
x=15 or -12
Therefore, the original no of boxes used is 15. 作者: r9r9r9r9 時間: 2016-8-11 11:53 AM