Reiny! Reiny! Reiny!
posted by Ellen on .
1. Oanh walked from her home to the grocery store at 3 mi/h and jogged home at 6 mi/h. Her total round trip was 15 minutes (1/4h). How far from Oanh's home is the grocery store? (use an equation to solve this)
Help, I am totally clueless on this.

let her time walking be t hours
then the distance she walked = 3t miles
let her time jogging back home be 1/4  t hours
so the distance she jogged = 6(1/4  t)
but aren't those two distances the same ?
so...
3t = 6(1/4  t)
I am sure you can solve this for t, then sub that value back into 3t to get the distance. 
Wait, I don't get it.
I solved
3t = 6 (1/4  t)
and got 11.66666666666....
and then what do I do?
..or did I do that wrong? 
3t = 6 (1/4  t)
3t = 3/2  6t
9t = 3/2
t = 3/18 = 1/6
then 3t, which was the distance
= 3(1/6) = 1/2
so the distance is 1/2 mile
check:
time walking = 1/2 ÷ 3 = 1/6 hour
time jogging = 1/2 ÷ 6 = 1/12 hour
1/6 + 1/12 = 2/12 + 1/12 = 3/12 = 1/4 hour 
Oh, i see.
thank you.