Show your working steps clearly.
1)If 18% of b is equal to 20% of b-7 , find the value of b.
F.1 maths questions
2007-12-01 10:45 pm
回答 (3)
2007-12-01 10:55 pm
✔ 最佳答案
bx18%= (b-7)x20%bx18/100= (b-7)x20/100
bx18/100x100/20= b-7
bx9/10=b-7
9b= 10(b-7)
9b=10b-70
9b-10b= -70
-b=-70
b=70
The answer is b = 70
參考: me
2007-12-01 11:01 pm
use equation to solve the question
b x 18% = (b-7) x 20%
b x 18/100 = (b-7) x 20/100
b x 9 /50 = (b-7) x 1/5
9b/50 = (b-7)/5 <--跟住交叉相乘
50(b-7) =5(9b)
50b-350 =45b
50b-45b =350
5b =350
b =70
計過岩GE=]
(b-7) x 20/100 <--好似li個咁' 即係(b-7) 乘以100分之20.
(b-7)/5 <-- li個就係5分之(b-7) ,,,(b-7)係分子~5係分母'
b x 18% = (b-7) x 20%
b x 18/100 = (b-7) x 20/100
b x 9 /50 = (b-7) x 1/5
9b/50 = (b-7)/5 <--跟住交叉相乘
50(b-7) =5(9b)
50b-350 =45b
50b-45b =350
5b =350
b =70
計過岩GE=]
(b-7) x 20/100 <--好似li個咁' 即係(b-7) 乘以100分之20.
(b-7)/5 <-- li個就係5分之(b-7) ,,,(b-7)係分子~5係分母'
參考: myself
2007-12-01 10:52 pm
B (18%) = 20% (B-7)
0.18B = 0.2B - 1.4
0.2B - 0.18B = 1.4
0.02B = 1.4
B = 70
0.18B = 0.2B - 1.4
0.2B - 0.18B = 1.4
0.02B = 1.4
B = 70
收錄日期: 2021-04-14 00:59:30
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