標題:
改一改 ok?
發問:
Correact the mistakes in the following questions. 1.A number is increased by 20%and the result is 48. The number = 48×(1-20%) = 38.4 2.If A is 10% greater than B and A = 110, then B = 110×(1-10%) = 99 請問有甚麼錯????
最佳解答:
( 1 ) 1 - 20% is very wrong as the Q asks for an increase but not a decrease. 48×(1-20%) means 48 is decreased by 20%. Corrections: Let the original number be x. x ( 1 + 20% ) = 48 x = 48 / ( 1 + 20% ) x = 40 ( 2 ) The calculation B = 110×(1-10%) means B is 10% less than A. Then the % of A greater than B: { ( 110 - 99 ) / 99 } x 100% = 11.1% ( cor. to 3 s.f. ) This contradicts with the statement A is 10% greater than B. Corrections: A = B ( 1 + 10% ) A = 1.1B B = A / 1.1 B = 110 / 1.1 = 100
其他解答:
1The number = 48/(1+20%) = 40 2 B = 110/(1+10%) = 100
改一改 ok?
發問:
Correact the mistakes in the following questions. 1.A number is increased by 20%and the result is 48. The number = 48×(1-20%) = 38.4 2.If A is 10% greater than B and A = 110, then B = 110×(1-10%) = 99 請問有甚麼錯????
最佳解答:
( 1 ) 1 - 20% is very wrong as the Q asks for an increase but not a decrease. 48×(1-20%) means 48 is decreased by 20%. Corrections: Let the original number be x. x ( 1 + 20% ) = 48 x = 48 / ( 1 + 20% ) x = 40 ( 2 ) The calculation B = 110×(1-10%) means B is 10% less than A. Then the % of A greater than B: { ( 110 - 99 ) / 99 } x 100% = 11.1% ( cor. to 3 s.f. ) This contradicts with the statement A is 10% greater than B. Corrections: A = B ( 1 + 10% ) A = 1.1B B = A / 1.1 B = 110 / 1.1 = 100
其他解答:
1The number = 48/(1+20%) = 40 2 B = 110/(1+10%) = 100
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