Question 384138
Lucas is 1/3 of a mile away from home, bicycling at 20mph,
 when his brother takes off on his bike to catch up.
 How fast must Lucas's brother go to catch him a mile from home?
:
We can are phrase this problem to:
Brother will have to travel 1 mile in the same time Lucas travels 2/3 of mile
Let s = brother's speed to accomplish this
:
Write a time equation; Time = dist/speed
{{{1/s}}} = {{{((2/3))/20}}}
Cross multiply
{{{2/3}}}s = 20
2s = 3(20)
2s = 60
s = 30 mph would be the brother's speed
:
:
Confirm this find the time of each, should be equal
1/30 = .033 hr
.67/20 = .033 hr