Alice is 6 years older than lois. In 2 years Alice will be twice as old as Lois. How old are they now?
Make an equation with a x varibale and a y variable
stuck on a mATH QUESTION. PLZ HELP?
2008-02-27 12:06 am
回答 (6)
2008-02-27 12:17 am
✔ 最佳答案
[02]Let the present age of Lois and alice be x and y years respectively
According to 1st condition,
y=x+6.
or,y-x=6......(1)
According to the second condition,
y+2=2(x+2)
or,y+2=2x+4
or,y-2x=4-2=2 .......(2)
Subtracting (2) from(1),we get
x=4
Therefore Lois is 4 yeaars old and Alice is 4+6 or 10 years old
2008-02-27 8:22 am
alice=6+2=8 8 years old
equation=6+2=x
lois=alice-8 years old " twice" as old as lois=lois's age
8/2=4 equal to half of alice's age
lois=4 years old
equation=8/2=y
equation=6+2=x
lois=alice-8 years old " twice" as old as lois=lois's age
8/2=4 equal to half of alice's age
lois=4 years old
equation=8/2=y
2008-02-27 8:20 am
A=L+6
A+2 = 2(L+2)
(use X for A above and Y for L- I used A and L for Alice and Lois to make this easy to follow.)
Now substitute the top equation in the bottom: Since L+6 = A,
(L+6)+2 = 2(L+2)
L+8 = 2L +4
(L + 8) - L = 2L(-L) +4
8 = L +4
8-4 = L-4
4 = L
Lois = 4, Alice = 10. in 2 years, lois = 6, Alice = 12.
A+2 = 2(L+2)
(use X for A above and Y for L- I used A and L for Alice and Lois to make this easy to follow.)
Now substitute the top equation in the bottom: Since L+6 = A,
(L+6)+2 = 2(L+2)
L+8 = 2L +4
(L + 8) - L = 2L(-L) +4
8 = L +4
8-4 = L-4
4 = L
Lois = 4, Alice = 10. in 2 years, lois = 6, Alice = 12.
2008-02-27 8:14 am
HI,
Let a = Alice's age now
Let l = Lois'es age now then
a = l + 6
a + 2 = 2(l+2)
now put l + 6 into the second equation giving us
l + 6 + 2 = 2l + 4 so l = 4
a = 4 + 6 = 10
Hope This Helps!!
Let a = Alice's age now
Let l = Lois'es age now then
a = l + 6
a + 2 = 2(l+2)
now put l + 6 into the second equation giving us
l + 6 + 2 = 2l + 4 so l = 4
a = 4 + 6 = 10
Hope This Helps!!
2008-02-27 8:14 am
right now Alice is 10 and Lois is 4.
2008-02-27 8:12 am
Let x = Lois's Age
Let y = Alice's age
but Alice is 6 yrs older than Lois so y=x+6
In 2 years, that is x+2 and y+2, Alice is twice as old as lois
y+2=2(x+2)
Solve for x and y:
y=x+6 sub into above equation
x+6+2=2(x+2)
x+8=2x+4
4=x so lois is 4 now, Alice is 4+6=10 now
and in 2 years, Lois will be 6 and Alice will be 12, twice the age, as expected
Let y = Alice's age
but Alice is 6 yrs older than Lois so y=x+6
In 2 years, that is x+2 and y+2, Alice is twice as old as lois
y+2=2(x+2)
Solve for x and y:
y=x+6 sub into above equation
x+6+2=2(x+2)
x+8=2x+4
4=x so lois is 4 now, Alice is 4+6=10 now
and in 2 years, Lois will be 6 and Alice will be 12, twice the age, as expected
收錄日期: 2021-05-04 06:49:58
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080226160656AAt6D7d