Math problem?
2015-06-06 1:46 pm
robert is 26 years older than matt ,so in 4 years robert will be 3 times the age of matt ,how old is robert now?
回答 (11)
2015-06-06 1:51 pm
✔ 最佳答案
let m = matt's age nowthen,
robert's age now = (m + 26)
in FOUR years...
matt's age = m + 4
robert's age = 3(m + 4)
m + 26 + 4 = 3(m + 4) = 3m + 12
2m = 18
m = 9
matt is 9 years old now
robert is 35 years old now
check...do something !!
2015-06-06 1:49 pm
Can't help you, I'm not good at calculus.
2015-06-07 3:59 am
robert is 26 years older than matt, so in 4 years robert will be 3 times the age of matt, how old is robert now?
robert's age
matt's age = m
r = 26 + m
in 4 years
r + 4 = 3 [ m + 4 ]
26 + m + 4 = 3m + 3.4
30 + m = 3m + 12
2m = 18
m = 9
robert's age now = r
= 26 + m
= 26 + 9
= 35
robert's age
matt's age = m
r = 26 + m
in 4 years
r + 4 = 3 [ m + 4 ]
26 + m + 4 = 3m + 3.4
30 + m = 3m + 12
2m = 18
m = 9
robert's age now = r
= 26 + m
= 26 + 9
= 35
2015-06-06 8:14 pm
Robert will always be 26 years older than Matt. In 4 years when Robert is 3 times the age of Matt, the difference in their ages will be twice Matt's age. This difference is still 26 years. So Matt's age will be 13 years. His age now is 13-4 = 9 and Robert's age now is 9+26 = 35.
2015-06-06 6:52 pm
Robert is 26 years older than Matt,
so in 4 years Robert will be 3 times the age of Matt,
how old is Robert now?
R - 26 = M
R + 4 = 3(M + 4)
30 = 2M + 12
M = 9
Robert is now 35 years old.
so in 4 years Robert will be 3 times the age of Matt,
how old is Robert now?
R - 26 = M
R + 4 = 3(M + 4)
30 = 2M + 12
M = 9
Robert is now 35 years old.
2015-06-06 4:15 pm
PRESENT AGES
-----------------------------
MATT = X
ROBERT = X+26
4 YEARS HENCE
--------------------------------
MATT = X+4
ROBERT = X+26 +4 = X+30
X+30= 3( X+4)
X+30 =3X+12
2X= 18
X = 9
MATT = 9 YEARS ROBERT = 35 YEARS ANSWER
CHECK
4 YEARS HENCE
----------------------------
MATT =13
ROBERT = 39
39= 3*13
-----------------------------
MATT = X
ROBERT = X+26
4 YEARS HENCE
--------------------------------
MATT = X+4
ROBERT = X+26 +4 = X+30
X+30= 3( X+4)
X+30 =3X+12
2X= 18
X = 9
MATT = 9 YEARS ROBERT = 35 YEARS ANSWER
CHECK
4 YEARS HENCE
----------------------------
MATT =13
ROBERT = 39
39= 3*13
2015-06-06 3:10 pm
r=m+26 and r+4=3(m+4)
From the first we can say that m=r-26, using this m in the second...
r+4=3(r-26+4)
r+4=3r-66
2r=70
r=35
So Robert is 35 years of age. (and Matt is 9 years old)
check...
35=9+26
35=35
35+4=3(9+4)
39=39
From the first we can say that m=r-26, using this m in the second...
r+4=3(r-26+4)
r+4=3r-66
2r=70
r=35
So Robert is 35 years of age. (and Matt is 9 years old)
check...
35=9+26
35=35
35+4=3(9+4)
39=39
2015-06-06 2:10 pm
Robert_______Matt
26 + x_________x
30 + x________x + 4
30 + x = 3 (x + 4)
30 + x = 3x + 12
28 = 2x
x = 9
Matt is 9
Robert is 35
26 + x_________x
30 + x________x + 4
30 + x = 3 (x + 4)
30 + x = 3x + 12
28 = 2x
x = 9
Matt is 9
Robert is 35
2015-06-06 2:10 pm
Create a system of equations
R = Robert's age M = Matt's age
R=M+26
R=3M <<in four years, so we'll subtract our final answer by 4
***
MULTIPLY [R=M+26] by 3
MULTIPLY [R=3M] by (-1)
The new system will be:
3R=3M+78
-R=-3M
***
SOLVE
3R = 3M +78
-R = -3M
-------------------------
2R = 0M +78
***
New equation: 2R=78
DIVIDE both sides by 2
(2R)/2=78/2
R=39
***
R=39-4
R=35
R = Robert's age M = Matt's age
R=M+26
R=3M <<in four years, so we'll subtract our final answer by 4
***
MULTIPLY [R=M+26] by 3
MULTIPLY [R=3M] by (-1)
The new system will be:
3R=3M+78
-R=-3M
***
SOLVE
3R = 3M +78
-R = -3M
-------------------------
2R = 0M +78
***
New equation: 2R=78
DIVIDE both sides by 2
(2R)/2=78/2
R=39
***
R=39-4
R=35
2015-06-06 1:55 pm
Robert is 35
Matt is 9
in 4 years:
Robert is 39 and Matt is 13
39/13= 3
Matt is 9
in 4 years:
Robert is 39 and Matt is 13
39/13= 3
2015-06-06 1:51 pm
r = m + 26 ... m = r - 26 <<< sub below
r + 4 = 3(m + 4)
r + 4 = 3m + 12 ... r = 3m + 8
r = 3(r - 26) + 8
r = 3r - 78 +8
-2r = - 70
r = 35 <<< answer
r + 4 = 3(m + 4)
r + 4 = 3m + 12 ... r = 3m + 8
r = 3(r - 26) + 8
r = 3r - 78 +8
-2r = - 70
r = 35 <<< answer
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