Summer Clouds
26/05/2017 at 08:34-
Call Alice's age is a
Betty's age is b
and Clara is c
Follow the threads , we have :
a + b + c = 29 (1)
b = a + 4 (2)
c = b + 6 (3)
Change (3) , (2) to (1)
a + b + c = a + (a + 4) + (b + 6)
<=> a + (a + 4) + (a + 10) = 29
=> 3a + 14 = 29
=> 3a = 15
=> a = 5
So , Alice's age is 5
Summer Clouds selected this answer. -
Lê Mạnh Tiến Đạt 31/05/2017 at 16:59Call Alice's age: a
Betty's age: b
Clara's age: c
(a,b,c∈∈N*)
According to the theme we have:
a+b+c=29a+b+c=29(1)b−a=4⇒b=a+4b−a=4⇒b=a+4(2)
c−b=6⇒c=b+6⇒c=a+4+6=a+10c−b=6⇒c=b+6⇒c=a+4+6=a+10(3)
Change (2)(3) to (1) we have:
(1)⇔a+b+c=29(1)⇔a+b+c=29a+a+4+a+10=29a+a+4+a+10=29
3a+14=293a+14=29
3a=29−14=153a=29−14=15
a=5a=5(satisfy)
Alice's age: 5 years old
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Tina 28/05/2017 at 17:54Call Alice's age: a
Betty's age: b
Clara's age: c
(a,b,c\(\in\)N*)
According to the theme we have:
\(a+b+c=29\)(1)\(b-a=4\Rightarrow b=a+4\)(2)
\(c-b=6\Rightarrow c=b+6\Rightarrow c=a+4+6=a+10\)(3)
Change (2)(3) to (1) we have:
\(\left(1\right)\Leftrightarrow a+b+c=29\)\(a+a+4+a+10=29\)
\(3a+14=29\)
\(3a=29-14=15\)
\(a=5\)(satisfy)
Alice's age: 5 years old