One number is twice another number. If the sum of the two numbers is 87, what are the two numbers?
2007-11-26 17:55:37 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
x=2y
x+y=87
3y=87... y = 29
x=2x29 = 58
2007-11-26 17:59:59 · answer #1 · answered by iceman 7 · 1⤊ 0⤋
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Let x be the first number
Let y be the second number
One number is twice another number
x = 2y (1)
the sum of the two numbers is 87,
x + y = 87 (2)
Bring 2y to the LHS in the first equation
x - 2y = 0 (3)
Multiply eq (2) by 2
2x + 2y = 174 (4)
Add (3) and (4)
x - 2y = 0
2x + 2y = 174
3x = 174
x = 174/3
x = 58
substitute x = 58 in (1)
x= 2y
58 = 2y
2y = 58
y = 58/2
y = 29
Therefore x = 58 y = 29
Proof is 58 is 2 * 29 as in (1)
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2007-11-27 02:20:44 · answer #2 · answered by A Little Sarcasm Helps 5 · 0⤊ 0⤋
x + 2x = 87
=> x = 87/3 = 29, 2x = 2(29) = 58
numbers are 29, 58
2007-11-27 02:01:45 · answer #3 · answered by sv 7 · 0⤊ 0⤋
14 and 12
2007-11-27 02:04:57 · answer #4 · answered by meg 1 · 0⤊ 0⤋
let x the first number
then the other number must be 2x
their sum is 87
so
x + 2x = 87
3x = 87
x = 29
2x = 58
:. the numbers are
29 and 58
2007-11-27 01:59:19 · answer #5 · answered by cedric 3 · 1⤊ 1⤋
29 and 58
x and 2x
so 3x=87
x=29
2x=58
2007-11-27 02:00:56 · answer #6 · answered by gnana 2 · 1⤊ 0⤋