Ron ran the first part of the distance with a constant speed of 20 km/h and the second part, 15 km/h. It took him 10 minutes less to run the first part than the second part. The second part was 5 km shorted than the first part. Find the total distance.
Can you explain how you did it?
2007-01-29 18:00:59 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Let the distance of the second part be x km.
So the distance of the first part is (x+5) ...(it is given that 2nd part is shorter than 1st by 5 km.)
Speed (S) = Distance/ Time ; so time = distance / speed
speed of 1st part =20 km/hr and for 2nd part = 15 km/hr (given)
so time taken for 1st part = (x+5)/20 hr. and for 2nd part= x/15 hr.
coverting hr. into mins. we get;
60 * (x+5)/20= 3(x+5)=(3x+15)mins; and 60*(x/15)=4xmins.
according to given condition; (10 mins less taken for first part)
3x+15 +10 = 4x
so 4x-3x=25
so x = 25
so (x+5)=25+5=30
so distance of 2nd part is 25 km. and of 1st part is x+5 = 30
Total dstance = 30 +25 =55 km.
And next time try to solve yourself atlest a few times after taking breaks to see if you can solve before asking someone.Okay.
Best of Luck!
2007-01-29 18:08:57 · answer #1 · answered by Richard 3 · 0⤊ 1⤋
Let x be the first part of the distance and y be the second part of the distance.By the given condition y = x -5[eqn.1]
He travelled x distance with a constant speed of (1/3)km per minute and y distance in (1/4)km per min. By the given condition
y/(1/4) - x/(1/3) = 10 that is 4y - 3x = 10[eqn. 2]
Solving eqn.1 and eqn. 2 we get x=20 and y=25
Therefore total distance = x+y = 20+25=45
2007-01-30 02:24:39 · answer #2 · answered by Joy C 1 · 0⤊ 0⤋
That Ron is quite a runner!
x/20 + 10/60 = y/15
x - 5 = y
3x + 10 = 4y
3x + 10 = 4x - 20
x = 30 km
y = 25 km
x + y = 55 km
3/2 + 1/6 =? 25/15
(9 + 1)/6 = 5/3
2007-01-30 02:39:10 · answer #3 · answered by Helmut 7 · 0⤊ 0⤋
Answer to the question is 15 Kms.
To sol. the problem i equate the difference of time between both the part to 10(min ie. 1/6 hrs) (given). like this
1/6=(x/20)-(x-5)/15
find x
and
just add x and x-5 which give you total distance.
2007-01-30 02:11:19 · answer #4 · answered by r_jain187 1 · 0⤊ 1⤋
let the first part be x KM
the second part would be x-5 KM
therefore the total distance is x+(x-5) KM
that is 2x-5KM is the total distance.
2007-01-30 02:24:21 · answer #5 · answered by Anonymous · 0⤊ 0⤋
distance=velocity times time
x=v.t
x1=20/60 .t
x2=15/60 .(t-10)
x2=x1-5
x1-5=15t/60-150/60
20t/60 - 5=15t/60-150/60
5t=150
t=30 minutes
x1=20/60*30=10 km
x2=10-5=5 km
total distance=10+5=15
2007-01-30 02:15:15 · answer #6 · answered by iyiogrenci 6 · 0⤊ 1⤋