Math
posted by Lisana .
Jessica can jog to work in 4/5 of an hour. When she rides her bike, it takes her 3/10 of an hour. If she rides 10 miles per hour faster than she jogs, how far away is her work?

She bikes at speed b, so d/b = 3/10
She jogs at speed j, so d/j = 4/5
But, b=j+10 so,
d/(j+10) = 3/10
d/j = 4/5
d = 3/10 (j+10) = 4j/5 = 8j/10
3(j+10) = 8j
30 = 5j
j=6
b=16
d=24/5 mi