標題:
Math (8條英文)
發問:
1. 2.75% of $840 is2. There are 40 students in a class.38 of them are boys.Find the % of girls in the class.3. A toy is sold at $68.If its cost is $85,find the loss rate.4. A car model is sold at 20% discount with a selling price of $120.Find the marked price.5. Find the simple interest on $4000 for... 顯示更多 1. 2.75% of $840 is 2. There are 40 students in a class.38 of them are boys.Find the % of girls in the class. 3. A toy is sold at $68.If its cost is $85,find the loss rate. 4. A car model is sold at 20% discount with a selling price of $120.Find the marked price. 5. Find the simple interest on $4000 for 18 months at 6% per annum. 6. A car of $160000 depreciates by 15% every year.Find the value of the car 4 years later. 更新: 7.Cindy paid $140 for a watch which was sold at a 30% discount. (a) Find the marked price. (b) What was the discount? 更新 2: 8. If number A increases bu 25% , it is equal to number B. Find the % of the original value of A to B.
最佳解答:
1. 2.75% of $840 is 840 x 2.75% = $23.1 2. There are 40 students in a class.38 of them are boys.Find the % of girls in the class. (40-38)/40 x 100% =5% 3. A toy is sold at $68.If its cost is $85,find the loss rate. (85-68)/85 x 100% =20% 4. A car model is sold at 20% discount with a selling price of $120.Find the marked price. 120 / (1-20%) =$150 5. Find the simple interest on $4000 for 18 months at 6% per annum. 4000 x (6% x 1.5) =$360 6. A car of $160000 depreciates by 15% every year.Find the value of the car 4 years later. 160000 x (1-15%)^4 = $83521 7.Cindy paid $140 for a watch which was sold at a 30% discount. (a) Find the marked price. 140/(1-30%) =$200 (b) What was the discount? 200 - 140 =$60 8. If number A increases by 25% , it is equal to number B. Find the % of the original value of A to B. (1+25%) x A = B the % of the original value of A to B. = A/B x 100% =A / 1.25A x 100% =80%
其他解答:
此文章來自奇摩知識+如有不便請留言告知
1. $840 x 2.75% = $23.1 2. No. of girls = 40 - 38 = 2 % of girls in the class = 2/40 x 100% = 5% 3. Loss rate = Loss/Cost price x 100% = ( 85 - 68 )/85 x 100% = 17/85 x 100% = 20% 4. Marked price x ( 1 - 20% ) = Selling price Marked price = Selling price ÷ ( 1 - 20% ) = $120 ÷ ( 1 - 20% ) = $120 x 100/80 = $150 5. Simple interest = Principal x Interest rate x Time = $4000 x 6% x 18/12 = $360 6. The value of the car 4 years later = $160000 x ( 1 - 15% )^4 = $160000 x ( 85/100 )^4 = $83521 7a. Marked price = $140 ÷ ( 1 - 30% ) = $140 ÷ 70% = $200 b. Discount = $200 - $140 = $60 8. A x ( 1 + 25% ) = B B = 1.25A The % of the original value of A to B = A/1.25A x 100% = 0.8 x 100% = 80%
留言列表
