when hydie was born her mother was 21 years old. at present hydies age is 30% of her mothers age. how old is hydie now? please help me with undrerstanding how to do this queastion.
2007-07-02 06:23:46 · 9 answers · asked by jusme 2 in Science & Mathematics ➔ Mathematics
Hydie's mum is always 21 years older than her.
At present, the remainding 70% is the difference between their ages.
70% = 21 years, so divide by 7
10% = 3 years, then multiply by 3
30% = 9 years
Hydie is 30% of her mum's age, so the answer is she is 9.
Then check the answer, just to be sure.
30% = 9 years, so divide by 3
10% = 3 years, so multiply by 10
100% = 30 years (this means 100% of Hydie's mum's age, so she's 30)
Take away Hydie's age
30 - 9 = 21 years At the beginning we said that the difference in their ages must always be 21 years, so this is right.
2007-07-02 06:44:39 · answer #1 · answered by Anonymous · 0⤊ 0⤋
lol im not using an X, ys lol just plain english.........
Firstly I just did trial and error and chose an age of the daughter. So I started with 15 etc.
did 15 divided by 3 (because shes 30% of her mums age) to give me 10% of her age and then x it but 10 to give me 100% to give me the mums age, but that gave me 50. I know thats wronge as the mum is only 21 years older than the daughter.
So I did that with a few numbers until there was a 21 age gap
9 / 30 x 100 = 30 and there is 21 years diff between them so The daughter is 9 and the mum is 30
2007-07-02 13:36:13 · answer #2 · answered by c.saunders1510@btinternet.com 2 · 0⤊ 0⤋
they have both aged 9 years so her mother is now 30.
9 is 30% of 30.
hydie is 9
2007-07-02 14:10:16 · answer #3 · answered by willygromit 3 · 0⤊ 0⤋
Let Hydie be x years of age
Mother is (x + 21) years of age
x = 0.3.(x + 21)
x = 0.3 x + 6.3
0.7 x = 6.3
x = 9
Hydie is 9 years old.
2007-07-04 02:23:54 · answer #4 · answered by Como 7 · 0⤊ 0⤋
h+21=m
3(m+t) / 10 = h+t
(3m+3t) / 10 = h+t
(3m+3t) / 10 = m-21+t
3m+3t = 10m-210+10t
-7m-7t = -210
-7(m+t) = -210
m+t = 30
That means 9 years after hydie was born.
When hydie was born she was 0 years old.
9 years after, she is 9.
2007-07-02 13:30:56 · answer #5 · answered by Anonymous · 0⤊ 0⤋
let hydies age is x
her mother age is y
y=x+21 --------------(1)
x = 30y/100 --------(2)
from (2) in (1)
y= (30y/100) + 21
100 y = 30y + 2100
70y = 2100
y = 2100/70
x = 30*2100/7000
x = 9 years <----------------> hydies age
it's ok ?
2007-07-02 13:38:42 · answer #6 · answered by Magd 1 · 0⤊ 0⤋
Let's call Heide's age x
Her mother's age is x + 21
x = 30(x + 21)/100
Now solve for x
2007-07-02 13:31:20 · answer #7 · answered by Anonymous · 0⤊ 0⤋
21*.30
=6.5 years old
This should be right!!
2007-07-02 13:31:17 · answer #8 · answered by Rahwa 4 · 0⤊ 0⤋
she is 9
factors of 3
dont no how but hubby worked it out....im thick
2007-07-02 13:28:22 · answer #9 · answered by only me 3 · 0⤊ 0⤋