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標題:
教我做英文的maths
發問:
1.it is given that a=30 and b=50.if a and b are decreased by 5% and 8% respectively,find the percentage decrease in their sum.2.A square has side 15 cm.if each side is increased by 20%,find (a) the percentage increase in perimeter.(b)the percentage increase in area.3.given that a=20 and b=15,(a)by... 顯示更多 1.it is given that a=30 and b=50.if a and b are decreased by 5% and 8% respectively, find the percentage decrease in their sum. 2.A square has side 15 cm.if each side is increased by 20%,find (a) the percentage increase in perimeter. (b)the percentage increase in area. 3.given that a=20 and b=15, (a)by what percentage is a greater than b? (b)by what percentage is b less than a? 更新: 4.the number of members in a Mathematics is increase by 10% to become 110.what is the original number of members? 5.the price of a computer is decreased by 20% to become $6000.what is the original price of the computer? 更新 2: 6.55% of F.1 students in a school pass an English test.if 110 students pass the test,find the total number of students in F.1
最佳解答:
1. (new value-original value)/original value x 100% original value is given as 30+50=80 the new value is 30(1-5%)+50(1-8%)=74.5 hence (74.5-80)/80 x 100%=-6.875% ∴The percentage decreased in their sum is 6.875% 2(a). The original side is 15 hence the perimeter is 15x4=60 The changed side is 15(1+20%)=18 hence the perimeter is 18x4=72 ∵The percentage changes=(new value-original value)/original value x 100% ∴The percentage increase in perimeter is (72-60)/60 x 100%=20% (b)The area of 15cm side is 225 The new area of 18cm side is 324 Therefore The percentage increase in area is (324-225)/225 x 100%=44% 3. I do not know what is the question about 4. The original number of members is 110÷(1+10%)=100 5. The original price of the computer is $6000÷(1－20%)=$7500 6. According to the formula (Sample/Population) x 100%=The percentage of sample in population let P be the unknown as population thus (110/P) x 100%=55% P=200 ∴The total number of students in F.1 is 200
其他解答:
教我做英文的maths
發問:
1.it is given that a=30 and b=50.if a and b are decreased by 5% and 8% respectively,find the percentage decrease in their sum.2.A square has side 15 cm.if each side is increased by 20%,find (a) the percentage increase in perimeter.(b)the percentage increase in area.3.given that a=20 and b=15,(a)by... 顯示更多 1.it is given that a=30 and b=50.if a and b are decreased by 5% and 8% respectively, find the percentage decrease in their sum. 2.A square has side 15 cm.if each side is increased by 20%,find (a) the percentage increase in perimeter. (b)the percentage increase in area. 3.given that a=20 and b=15, (a)by what percentage is a greater than b? (b)by what percentage is b less than a? 更新: 4.the number of members in a Mathematics is increase by 10% to become 110.what is the original number of members? 5.the price of a computer is decreased by 20% to become $6000.what is the original price of the computer? 更新 2: 6.55% of F.1 students in a school pass an English test.if 110 students pass the test,find the total number of students in F.1
最佳解答:
1. (new value-original value)/original value x 100% original value is given as 30+50=80 the new value is 30(1-5%)+50(1-8%)=74.5 hence (74.5-80)/80 x 100%=-6.875% ∴The percentage decreased in their sum is 6.875% 2(a). The original side is 15 hence the perimeter is 15x4=60 The changed side is 15(1+20%)=18 hence the perimeter is 18x4=72 ∵The percentage changes=(new value-original value)/original value x 100% ∴The percentage increase in perimeter is (72-60)/60 x 100%=20% (b)The area of 15cm side is 225 The new area of 18cm side is 324 Therefore The percentage increase in area is (324-225)/225 x 100%=44% 3. I do not know what is the question about 4. The original number of members is 110÷(1+10%)=100 5. The original price of the computer is $6000÷(1－20%)=$7500 6. According to the formula (Sample/Population) x 100%=The percentage of sample in population let P be the unknown as population thus (110/P) x 100%=55% P=200 ∴The total number of students in F.1 is 200
其他解答:
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