I'm desperate, can anyone help me?
Good evening,
Hi, I've been given a math problem that I'm supposed to solve (I got it from school). I have to hand it in on Monday and I can't do it on the weekend. So I only have today. Yes, I know, maybe I shouldn't do any more math problems now, I have the whole day for that. But unfortunately it's not that easy. And we have a really weird math teacher who seems to explain nothing. And yet we're supposed to know everything 😭. Well, when she does explain things, they're really bad. I've been trying to solve this problem for ages, using YouTube and things like that, but I still don't understand it! Can anyone help me?
Thank you in advance for your answers 🎈
(2 votes)
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The general physical formula to be used for this is the one for the speed of a uniform movement:
v = s/t
with
v = speed in km/h
s = distance in km
t = time in h
Laura and Pia set a distance of 20 km together, so
s(L) + s(P) = 20 km
The speed formula, reshaped after the distance is:
= v = t
You also know the speed of the two girls:
v(L) = 15 km/h and v(P) = 10 km/h
The time required for the meeting is: t(L) = t(P) = t
Both girls need to go from their starting point to the meeting point.
So all assembled:
20 km = s(L) + s(P) = v(L) * t + v(P) * t
20 km = (v(L) + v(P) * t
20 km = (15 km/h + 10 km/h) * t
20 km = (25 km/h) * t
t = 20 km/25 km/h = 0.8 h
That’s the result. If you want, you can convert it in minutes. If an hour has 60 minutes, how many minutes are then 0.8 hours?
Do you understand my approach? If not, please ask.
Thank you for the detailed answer! 😊. I’ll take a closer look at her tomorrow morning! I ask questions!
Thanks also for giving the asterisk as a sign for the most helpful answer. I will then look again later (just before the start of school) to see if everything has been clear for you.
I had a little question. Actually, the formula should be t=v*s, right? But you used t=s/V in your example. Do I have a mistake?
Your proposal t = v * s is actually based on a mistake of thought.
If you transform a mathematical equation, you always have to perform the same operation on both sides of the equation. How to get to t = s / v.
It must also come with the units of measure. The time is measured in seconds or hours. If one multiplys the speed (in km/h) by the way (in km), one would come to the unit square kilometers per hour. This would be a surface covering that is achieved in a time unit, but no time.
Oh! I think I understand! Thanks a lot
I just looked at her again. I think I understood everything that far. Thanks again 🍀
Great!
You can set up simple equations. Other approach would be to assume that Laura is driving the whole line at 25 km/h and Laura isn’t. The result is the same, but perhaps easier to expect.
20/25 = 0.8 hours = 48 minutes.
Time= Distance/speed
Here would be a possible approach to the outcome:
https://www.youtube.com/watch?v=BoSA9I6YnNw
Thanks the Viedeos was very helpful! 😊
t * ( 15 + 10 ) km/h = 20 km
This follows: t = (20/25 )h = (4/5)h = 48 minutes
ChadGPT is there for you🤌🤌
also Gemini and everything free, very good
🤌
s = v * t (one must know this formula)
s1 = 15km/h * t
s2 = 10km/h * t
Together, they should cover 20km, so:
15km/h * t + 10km/h * t = 20km
Dissolve after t:
t * (15km/h + 10km/h) = 20km
t = 20km / (25km/h)
t = 0,8h = 48m
not meters (m), but minutes (min)❗
t = 0,8 h = 48 min
min… yes of course