heshamelaziry wrote:Johnny travels a total of one hour to and from school. On the way there he jogs at 5 miles per hour and on the return trip he gets picked up by the bus and returns home at 20 miles per hour. How far is it to the school?

a) 2 miles

b) 4 miles

c) 4.8 miles

d) 8 miles

e) 10 miles


A) The Algebra Student says: I will work with the rates and I can see that one is four times the other in terms of time, because D=R*T (Distance = Rate X Time). I know they are inversely related. So 5T= 1 hour. Therefore T=.2 hours. I can take either the bus speed or the bicycle speed and plug in: 20 miles an hour multiplied by .2 hours results in 4 miles. We check the work and we are right.


How is it that 5t=1 ? where is the inverted relationship. I am totally lost.....

mohitsharda wrote:

heshamelaziry wrote:Johnny travels a total of one hour to and from school. On the way there he jogs at 5 miles per hour and on the return trip he gets picked up by the bus and returns home at 20 miles per hour. How far is it to the school?

a) 2 miles

b) 4 miles

c) 4.8 miles

d) 8 miles

e) 10 miles


A) The Algebra Student says: I will work with the rates and I can see that one is four times the other in terms of time, because D=R*T (Distance = Rate X Time). I know they are inversely related. So 5T= 1 hour. Therefore T=.2 hours. I can take either the bus speed or the bicycle speed and plug in: 20 miles an hour multiplied by .2 hours results in 4 miles. We check the work and we are right.


How is it that 5t=1 ? where is the inverted relationship. I am totally lost.....

5t =1 hour because in the question it says that Johnny travels a total of 1 hour.
Also, the speed is 5 while going and 20 while coming back.
So, we can take t as the time spent coming back, and 4t as the time spent going.
Total = 5t = 1 hour