Math Is Fun Forum
Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °
You are not logged in.
- Topics: Active | Unanswered
Pages: 1
#1 2009-07-01 22:17:59
- macy
- Guest
Speed and distance
Please help me
Peter rides the bicycle at 10km/h from his home to the park at 10am. Half and hour later his sister
tries to catch him up at 12km/h. How long will it take her to meet him.
#2 2009-07-01 22:32:10
- luca-deltodesco
- Member
- Registered: 2006-05-05
- Posts: 1,470
Re: Speed and distance
moving at 10km/h, after 30 minutes Peter will have travelled 10*0.5 = 5km (since 30minutes = 0.5hours)
at time t (hours), the sister will have moved 12t, whilst peter moves 10t, but peter is also 5km ahead of his sister
so you have the equation
12t = 5 + 10t
2t = 5
t = 2.5hrs
Last edited by luca-deltodesco (2009-07-01 22:33:55)
The Beginning Of All Things To End.
The End Of All Things To Come.
Offline
#3 2009-07-01 22:43:19
- Macy
- Guest
Re: Speed and distance
thank you
Pages: 1