中3~Percentages[要列式]

In 2004, manufacturing :$60 000 000 X (1-20%) = $48 000 000
shipping : $240 000 000 X (1-10%) = $216 000 000

total profit of the enterprise in 2003 :
Shipping $240 000 000+ Construction $500 000 000 + Manufacturing $60 000 000
= $800 000 000

total profit of the enterprise in 2004 :
$800 000 000 X (1-15%)= $680 000 000

$680 000 000 = $48 000 000 +$216 000 000+ $500 000 000 (1- A%)
$680 000 000 - $48 000 000 - $216 000 000 = $500 000 000 (1- A%)
$416 000 000/ $500 000 000 =1- A%
0.832 -1= - A%
0.168 = A/100
A = 16.8%

If u think that the amount of the money is too big, u can cut out the last six zero (ie. 000 000) to calculate. The answer is the percentage decrease of its profit from construction was 16.8%.

I hope i can help u ~

New profit from maufacturing
= $60 000 000 x (1 - 20%)
= $48 000 000

New profit from shipping
= $240 000 000 x (1 - 10%)
= $216 000 000

New total profit
= ($240 000 000 + $500 000 000 + $60 000 000) x (1 - 15%)
= $680 000 000

New profit from construction
= $680 000 000 - $216 000 000 - $48 000 000
= $416 000 000

Percentage decrease
= [(500 000 000 - 416 000 000) / 500 000 000] x 100%
= 16.8%

If there is a mistake, please inform me.