標題:
數學的問題!!!!!!!!!!!!!!!!!!!!!!!!!!
發問:
Peter is 12 years old and his grandfather is 63 years old now. (Answer in Algebraic Equation)(process and construction) (a)After how many years' time will Peter's age be 1/4 of his grandfather's age? (b)How many years ago was grandfather's age 18 times Peter's? Thank you!
a. Let grandfather age be y. Let Peter age be 1/4y. 1/4x+63=12+x -3/4x=-51 x=17*4 x=68 68-63=5 So after 5 years timen will peter age be 1/4 of his grand father age. b. Let grand father age be x. Let peter age be x/18 x+12=x/18+63 18x+216=x+1134 17x=1134-216 17x=918 x=57 63-57=9 So 9 years ago was grandfather age18 times peter. Only answer: a.after 5 years. b.9 years ago.
其他解答:
(a) Let x be the number of yrs 12 + x / 63 + x = 1/4 48+ 4x = 63 +x x=5 (b) Let X be the number of years 63-X = 18(12-X) 63-X = 216 - 18X 17X = 153 X= 9 笑死我的問題 哈哈.)|||||(a) Assume x years later, Peter's age will be 1/4 of his grandfather's age 12 + x = (63 + x) /4 (12 + x) * 4 = (63 + x) /4 * 4 48 + 4x = 63 + x 4x - x = 63 - 48 3x = 15 x = 5 (b) Assume y years ago, grandfather's age was 18 times Peter's 63 - y = (12 - y) * 18 63 - y = 216 - 18y 18y - y = 216 - 63 17y = 153 y = 9
數學的問題!!!!!!!!!!!!!!!!!!!!!!!!!!
發問:
Peter is 12 years old and his grandfather is 63 years old now. (Answer in Algebraic Equation)(process and construction) (a)After how many years' time will Peter's age be 1/4 of his grandfather's age? (b)How many years ago was grandfather's age 18 times Peter's? Thank you!
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最佳解答:a. Let grandfather age be y. Let Peter age be 1/4y. 1/4x+63=12+x -3/4x=-51 x=17*4 x=68 68-63=5 So after 5 years timen will peter age be 1/4 of his grand father age. b. Let grand father age be x. Let peter age be x/18 x+12=x/18+63 18x+216=x+1134 17x=1134-216 17x=918 x=57 63-57=9 So 9 years ago was grandfather age18 times peter. Only answer: a.after 5 years. b.9 years ago.
其他解答:
(a) Let x be the number of yrs 12 + x / 63 + x = 1/4 48+ 4x = 63 +x x=5 (b) Let X be the number of years 63-X = 18(12-X) 63-X = 216 - 18X 17X = 153 X= 9 笑死我的問題 哈哈.)|||||(a) Assume x years later, Peter's age will be 1/4 of his grandfather's age 12 + x = (63 + x) /4 (12 + x) * 4 = (63 + x) /4 * 4 48 + 4x = 63 + x 4x - x = 63 - 48 3x = 15 x = 5 (b) Assume y years ago, grandfather's age was 18 times Peter's 63 - y = (12 - y) * 18 63 - y = 216 - 18y 18y - y = 216 - 63 17y = 153 y = 9
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