Maths Question!! 20 points!!!!!!
2017/06/17 10:50
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Maths Question!! 20 points!!!!!!
發問:
1).The TV station broadcasts 16 hours every day. 20% of the time os for advertisements, 40% for news and 40% for music programmes. If the total time for advertisements and news is incease by 20%, what is the percentage decrease time for music programmes?2). An alloy, which contains 70%iron and 30% aluminium,... 顯示更多 1).The TV station broadcasts 16 hours every day. 20% of the time os for advertisements, 40% for news and 40% for music programmes. If the total time for advertisements and news is incease by 20%, what is the percentage decrease time for music programmes? 2). An alloy, which contains 70%iron and 30% aluminium, weighs 20kg. If add 5 kg copper into the alloy, what percentages are iron, aluminium and coppr in the mew alloy respectively? Please show the work out and explan!!! Thanks!!!
最佳解答:
1. New total time for advertisements and news = (16 h) x (20% + 40%) x (1 + 20%) = 11.52 h New time for music programmes = (16 - 11.52) h = 4.48 h Original time for music programmes = 16 h x 40% = 6.4 h Precentage decrease time for music programmes = [(6.4 - 4.48)/6.4] x 100% = 30% ===== 2. Mass of iron in the new alloy = Mass of iron in the original alloy = (20 kg) x 70% = 14 kg Mass of aluminium in the new alloy = Mass of aluminium in original alloy = (20 kg) x 30% = 6 kg Mass of copper in the new alloy = 5 kg Total mass of the new alloy = (20 + 5) kg = 25 kg Percentage of iron in the new alloy = (14/25) x 100% = 56% Percentage of aluminium in the new alloy = (6/25) x 100% = 24% Percentage of copper in the new alloy = (5/5) x 100% = 20% Ans: The new alloy contains 56% iron, 24% aluminium and 20% copper. =
其他解答:
1) 原本: advertisement + news: 60% = 9.6h music: 6.4h 之後: advertisement + news: 9.6*120%=11.52 music: 16-11.52=4.48 2) iron: 14kg 56% aluminium: 6kg 24% copper: 5kg 20% total: 25kg 100%|||||20mm ). An alloy, which contains 70%iron
Maths Question!! 20 points!!!!!!
發問:
1).The TV station broadcasts 16 hours every day. 20% of the time os for advertisements, 40% for news and 40% for music programmes. If the total time for advertisements and news is incease by 20%, what is the percentage decrease time for music programmes?2). An alloy, which contains 70%iron and 30% aluminium,... 顯示更多 1).The TV station broadcasts 16 hours every day. 20% of the time os for advertisements, 40% for news and 40% for music programmes. If the total time for advertisements and news is incease by 20%, what is the percentage decrease time for music programmes? 2). An alloy, which contains 70%iron and 30% aluminium, weighs 20kg. If add 5 kg copper into the alloy, what percentages are iron, aluminium and coppr in the mew alloy respectively? Please show the work out and explan!!! Thanks!!!
最佳解答:
1. New total time for advertisements and news = (16 h) x (20% + 40%) x (1 + 20%) = 11.52 h New time for music programmes = (16 - 11.52) h = 4.48 h Original time for music programmes = 16 h x 40% = 6.4 h Precentage decrease time for music programmes = [(6.4 - 4.48)/6.4] x 100% = 30% ===== 2. Mass of iron in the new alloy = Mass of iron in the original alloy = (20 kg) x 70% = 14 kg Mass of aluminium in the new alloy = Mass of aluminium in original alloy = (20 kg) x 30% = 6 kg Mass of copper in the new alloy = 5 kg Total mass of the new alloy = (20 + 5) kg = 25 kg Percentage of iron in the new alloy = (14/25) x 100% = 56% Percentage of aluminium in the new alloy = (6/25) x 100% = 24% Percentage of copper in the new alloy = (5/5) x 100% = 20% Ans: The new alloy contains 56% iron, 24% aluminium and 20% copper. =
其他解答:
1) 原本: advertisement + news: 60% = 9.6h music: 6.4h 之後: advertisement + news: 9.6*120%=11.52 music: 16-11.52=4.48 2) iron: 14kg 56% aluminium: 6kg 24% copper: 5kg 20% total: 25kg 100%|||||20mm ). An alloy, which contains 70%iron
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