Discussion
Just doing some 11+ papers with the daughter and one question got me stumped.
Baz is 5 years older than his brother and 1 year younger than his cousin.
His uncle is 3 times the age of his cousin and 4 times the age of his brother.
How old is Baz?
how does one go about working this out? I know it's a number that will give the same result x3 and x4 but there's got to be a quick way..
Baz is 5 years older than his brother and 1 year younger than his cousin.
His uncle is 3 times the age of his cousin and 4 times the age of his brother.
How old is Baz?
how does one go about working this out? I know it's a number that will give the same result x3 and x4 but there's got to be a quick way..
dfen5 said:
Just doing some 11+ papers with the daughter and one question got me stumped.
Baz is 5 years older than his brother and 1 year younger than his cousin.
His uncle is 3 times the age of his cousin and 4 times the age of his brother.
How old is Baz?
how does one go about working this out? I know it's a number that will give the same result x3 and x4 but there's got to be a quick way..
4(x-5) = 3(x+1)Baz is 5 years older than his brother and 1 year younger than his cousin.
His uncle is 3 times the age of his cousin and 4 times the age of his brother.
How old is Baz?
how does one go about working this out? I know it's a number that will give the same result x3 and x4 but there's got to be a quick way..
4x - 20 = 3x + 3
4x - 3x = 3 - 20
X = -17
You've written it down incorrectly...
dfen5 said:
Just doing some 11+ papers with the daughter and one question got me stumped.
Baz is 5 years older than his brother and 1 year younger than his cousin.
His uncle is 3 times the age of his cousin and 4 times the age of his brother.
How old is Baz?
how does one go about working this out? I know it's a number that will give the same result x3 and x4 but there's got to be a quick way..
My thought process was; The cousin (c) is six years older than the brother (b), so c=b+6.Baz is 5 years older than his brother and 1 year younger than his cousin.
His uncle is 3 times the age of his cousin and 4 times the age of his brother.
How old is Baz?
how does one go about working this out? I know it's a number that will give the same result x3 and x4 but there's got to be a quick way..
Also we know, from the uncle's age that 3*c = 4*b
Putting these together;
3(b + 6) = 4b
3b + 18 = 4b
b = 18
So Baz = 18 + 5 = 23.
EliseNick said:
My thought process was; The cousin (c) is six years older than the brother (b), so c=b+6.
Also we know, from the uncle's age that 3*c = 4*b
Putting these together;
3(b + 6) = 4b
3b + 18 = 4b
b = 18
So Baz = 18 + 5 = 23.
We have a winner. I still don't get how you did that.. Doh!Also we know, from the uncle's age that 3*c = 4*b
Putting these together;
3(b + 6) = 4b
3b + 18 = 4b
b = 18
So Baz = 18 + 5 = 23.
Edit. Got it now, thank you.
Edited by dfen5 on Monday 11th April 21:00
schmunk said:
4(x-5) = 3(x+1)
4x - 20 = 3x + 3
4x - 3x = 3 - 20
X = -17
You've written it down incorrectly...
Correct answer is 23.4x - 20 = 3x + 3
4x - 3x = 3 - 20
X = -17
You've written it down incorrectly...
This algebra from schmunk is correct up to the line
4x - 3x = 3 - 20 which should be 4x - 3x = 3 +20; you just got "-" instead of "+" (adding 20 to both sides)
dfen5 said:
We have a winner. I still don't get how you did that.. Doh!
Does this help?Let Bz = Baz, Br = Brother, C = cousin, U = uncle.
We know that:
(1) Bz = Br + 5
(2) Bz = C - 1
(3) U = 3 x C
(4) U = 4 x Br
(3),(4) => 3C = 4Br (5)
Substituting in (5) for C from (2) and Br from (1) => 3 x (Bz+1) = 4x(Bz-5)
=> 3Bz + 3 = 4Bz - 20
=> Bz = 23
=> Br = 18
=> C = 24
=> U = 72
(as above!)
M4cruiser said:
schmunk said:
4(x-5) = 3(x+1)
4x - 20 = 3x + 3
4x - 3x = 3 - 20
X = -17
You've written it down incorrectly...
Correct answer is 23.4x - 20 = 3x + 3
4x - 3x = 3 - 20
X = -17
You've written it down incorrectly...
This algebra from schmunk is correct up to the line
4x - 3x = 3 - 20 which should be 4x - 3x = 3 +20; you just got "-" instead of "+" (adding 20 to both sides)
Edited by schmunk on Monday 11th April 21:27
V8LM said:
Yes, written down wrong:
Bz = 5 Br
Bz = C - 1
U = 3 C
U = 4 Br
Bz = 5 U / 4
Bz = 5 3C / 4
Bz = 5 3(Bz + 1) / 4
4 Bz = 15 Bz + 5
11 Bz = -5
Bz = -5 / 11
?
Ignore the drivel above.Bz = 5 Br
Bz = C - 1
U = 3 C
U = 4 Br
Bz = 5 U / 4
Bz = 5 3C / 4
Bz = 5 3(Bz + 1) / 4
4 Bz = 15 Bz + 5
11 Bz = -5
Bz = -5 / 11
?
Bz = Br + 5 (NOT 5 Br).
Bz = C - 1
U = 3 C
U = 4 Br
Bz = U / 4 + 5
Bz = 3C / 4 + 5
Bz = 3 (Bz + 1) / 4 + 5
4 Bz = 3 (Bz + 1) + 20
Bz = 23
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