Amanda is 12 years old and is 2/7 times her fathers age. how many years ago was her father 4 times as old as her? Explain

Question

Amanda  is 12 years old and is 2/7 times her fathers age. how many years ago was her father 4 times as old as her? Explain

anonymous · Answer

I need like why this answer is right and explaining the thinking

zzr0ck3r · Answer

1)   Amanda is 2/7 of her fathers age
$$2) \ \ Amandas\ \ age = \frac{2}{7}fathers \ age$$
lets think why these two things are the same

50 cents is 1/2 of 1 dollar
$$.50=\frac{1}{2}1$$

ok so now we just need to plug in amandas age and then solve for fathers age
$$12=\frac{2}{7}f\ \ \text{where f is her father}$$


does this make sense?

zzr0ck3r · Answer

brb phone...

anonymous · Answer

yeah....... but I need some thing leas complicated

zzr0ck3r · Answer

it does not get less complicated than
12 = 2/7 x

anonymous · Answer

*less

jdoe0001 · Answer

she's 2/7 the age of her father today, she's 12
so we know that 12 is 2/7 of HIS age, that is

f = father
a = alice

$\bf a = 12\qquad a = \cfrac{2}{7}f\ \quad \
12 = \cfrac{2}{7}f$

solve for "f" to get HIS age today

anonymous · Answer

no the explanation is complicated

zzr0ck3r · Answer

lol in what way is this any different than what I said?

jdoe0001 · Answer

heheh it isn't =)

zzr0ck3r · Answer

seems pointless and more confusing then for the user?

anonymous · Answer

im being taught 5 grades ahead!!!

jdoe0001 · Answer

hmmm... ahem.. I see

anonymous · Answer

im in1st grade

anonymous · Answer

im happy I can do quadratics though

jdoe0001 · Answer

hmm.... so.... seems to me this exercise may not apply to you then, since it involves fractions

anonymous · Answer

i know fractions!!!!!!!!!!!!!!

anonymous · Answer

ohhhh ok i get the explanation now!

anonymous · Answer

move on

jdoe0001 · Answer

$\bf a = 12\qquad a = \cfrac{2}{7}f\ \quad \
a = a\implies 12 = \cfrac{2}{7}f$

anonymous · Answer

yes i saw that

jdoe0001 · Answer

well, anyhow, what would be his age today then?

anonymous · Answer

42 years old

anonymous · Answer

gah! lag!!

jdoe0001 · Answer

so, he's 42 today, she's 12
how many years ago was she 1/4 his age, or he was 4 times her age?

well, she's 12, we can only go back 12 years, otherwise she wasn't born yet =)

so, when she was 11, he was 41

is 11 * 4 = 14?  no

so, when she was 10, he was 40

what do you think?

anonymous · Answer

yesss!!!

jdoe0001 · Answer

:)

jdoe0001 · Answer

11 * 4 = 41   doh. anyhow.. just a typo,, but yes

when she's 10, he's 4 times 10

anonymous · Answer

il get problems after this I GOT 100 PROBLEMS

anonymous · Answer

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