1) One number is 4 less than 3 thimes as larger as another. Find the numbers, if three times the larger is 15 larger than six times the smaller.
2) Peter has $25 more than Alex. Kevin has $13 less than Alex. Andrew has $5 more than twice as much as pete. Kelley has three times as much as Alex. Together they have $227. How much more money does Andrew have than Kelly?
math problem; problem solving 2 questions
2007-09-11 2:29 pm
回答 (2)
2007-09-11 3:25 pm
✔ 最佳答案
1) Let x and y be the larger and the smaller number respectively.x+4=3y --------------------------------(1)
3x -15 = 6y ----------------------------------(2)
From (2), x -5 = 2y
x = 2y + 5 ------------------(3)
Put (3) into (1),
(2y+5)+4 = 3y
y =9
Put y = 9 into (1),
x + 4 = 3(9)
x = 23
2) Let $x be the amount of money that Alex has.
Peter has x + 25
Kevin has x - 13
Andrew has 2(x + 25) + 5
Kelly has 3x
x + (x + 25) + (x - 13) + [2(x + 25) + 5] + 3x = 227
8x + 67 = 227
x = 20
The money that Andrew has more than Kelly
= 2(20 + 25) + 5 - 3(20)
= 90 + 5 - 60
= 35
2007-09-11 3:48 pm
!.
y+4=3x------------------------(1)
3y-15=6x---------------------(2)
2y+8=6x---------------------(1)x2=(3)
y=23---------------------------(2)-(3)
x=(23+4)/3
x=9
2.
let Peter has $x, Alex has $y, Kevin has $z, Andrew has $a, Kelly has $b,
now ask a-b=?
x-25=y----------------------(1)
z+13=y---------------------(2)
a-5=2x---------------------(3)
b=3y------------------------(4)
x+y+z+a+b=227----------(5)
x=y+25
z=y-13
a=2x+5
a=2y+55
y+25+y+y-13+2y+55+3y=227
8y=160
y=20
a=2(20)+55
a=95
b=3(20)
b=60
a-b=95-60
a-b=35
Andrew have $35 more than Kelly
y+4=3x------------------------(1)
3y-15=6x---------------------(2)
2y+8=6x---------------------(1)x2=(3)
y=23---------------------------(2)-(3)
x=(23+4)/3
x=9
2.
let Peter has $x, Alex has $y, Kevin has $z, Andrew has $a, Kelly has $b,
now ask a-b=?
x-25=y----------------------(1)
z+13=y---------------------(2)
a-5=2x---------------------(3)
b=3y------------------------(4)
x+y+z+a+b=227----------(5)
x=y+25
z=y-13
a=2x+5
a=2y+55
y+25+y+y-13+2y+55+3y=227
8y=160
y=20
a=2(20)+55
a=95
b=3(20)
b=60
a-b=95-60
a-b=35
Andrew have $35 more than Kelly
參考: me
收錄日期: 2021-04-13 13:25:20
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