This year your brother Jack will be 2 years from being twice as old as your sister Jen. The sum of Jack's age and three times Jens age is 66. How old is Jen?

Question

This year your brother Jack will be 2 years from being twice as old as your sister Jen.  The sum of Jack's age and three times Jens age is 66.  How old is Jen?

anonymous · Answer

could you type that equation out for me?

anonymous · Answer

b+2=1/2 *(s)

b+3s=66

anonymous · Answer

i guess use the substitution method to solve

anonymous · Answer

i got 

b = 54/7, s = 136/7

b = 7.714, s = 19.428

anonymous · Answer

I think i might have   made a mistake nvrmnd

amistre64 · Answer

$$2b\pm 2 = s$$

amistre64 · Answer

er.. $$2(b\pm2)=s$$
sounds better to me

amistre64 · Answer

and since$$b+3s=66$$subbing in is good$$b+3(2(b\pm2)) = 66$$

amistre64 · Answer

i hate words in math ....

amistre64 · Answer

$b \pm 2$ = 2s ; and that my final offer :)

amistre64 · Answer

$$b = 2s\pm2$$$$2s\pm2+3s=66$$$$5s\pm2=66$$$$5s=66\pm2$$$$s=\frac{66\pm2}{5}$$

amistre64 · Answer

...just check their birth certificates :)

anonymous · Answer

thanks

lgbasallote · Answer

you are a horrible brother/sister if you dont know your own siblings' birthday and have to use algebra to figure out :(

anonymous · Answer

@superhelper   As you see these can be tricky to set up.  The answer given is fractional which isn't what was wanted, I think.  I start by assuming that in 2 years Jack will be twice Jen's age in two years.

I tried to solve the problem by guessing that Jen's age now is about 1/5 of 66.
 
Jen = 11 now, will be 13;  Jack is 24, will be 26;  3 times 11 + 24 = 57
Jen = 12 now, will be 14;  Jack is 26, will be 28;  3 times 12 + 26 = 62
Jen = 13 now, will be 15;  Jack is 28, will be 30;  3 times 13 + 28 = 67

This doesn't seem to give a whole number 66 answer!

Change my assumption, in 2 years Jack will be twice Jen's age now.

Jen = 12 now;  Jack is 22, will be 24;  3 times 12 + 22 = 58
Jen = 13 now;  Jack is 24, will be 26;  3 times 13 + 24 = 63
Jen = 14 now;  Jack is 26, will be 28;  3 times 14 + 26 = 68

Seems to be something wrong with the problem… ?  Recheck the text.

anonymous · Answer

the way i tried out this problem i didn't assume.  what i wrote was right.  i think you are suppose to come out with a decimal

I think i just figured it out

its hard to explain in words. but you do end up with a decimal

anonymous · Answer

Thanks for the update.

anonymous · Answer

yup