StarDust845 wrote:What does "heat" (no pun intended) below mean ?

Calista.

6. A and B ran a race of 480 m. In the first heat, A gives B a head start of 48 m and beats him by 1/10th of a minute. In the second heat, A gives B a head start of 144 m and is beaten by 1/30th of a minute. What is B’s speed in m/s?
(A) 12
(B) 14
(C) 16
(D) 18
(E) 20

maybe heat means race? ... "In the first race..."

I am also trying to answer these though problems, the problem is that some answers in that document are not correct (ie. 1). I found a while ago a post in thos forum about these problems to try to figure which ones where not correct...but i cant find it anymore, can someone please put a link to it!!

Thanks a lot!

I should have been more specific. It's not the heat, I just don't understand this problem.

Calista.

Calista, what they are asking you is to find the speed of B.....the tough thing here is that they compare the speed of B with the speed of A, but the do not give you neither speeds.

Instead they give you two diferent races so that you can determine it.

Does this explanation help you?

"A gives B a head start of x meters" What does it mean?

You're right, a heat is a race. Usually, if there are more runners than lanes on the track, there will be more than 1 heat of the same race. Then, the winners of each heat compete against each other to determine the overall winner.

A head start is allowing someone to either start ahead of you in time or distance. In this case, B is starting 48 meters closer to the finish line (48m from where A is starting), so B's total distance will be shorter.

Is B the correct answer?

Here is how i tried..not sure if it is correct.

HEAT could be a race.

Case 1 : A won by 1/10 of a minute (6 seconds)
i.e Tb-Ta=6

I think giving a headstart means B had to run 48m less or A started race when B was already 48 m ahead..

i.8 (432/Sb)-(480/Sa)=6 -----Equation I

Case 2 : A lost by 1/30th of a minute.
1.e Ta-Tb=2

1.e (480/Sa)-(336/Sb)=2 ----- Equation II

If we add Equation I and II, we get

106/Sb=8

=> Sb=13.25 that is close to 14..

Let me know the correct answer.

Thanks for the reply.

Your approach is correct but your arithmetic is incorrect.

When you add the equations you get 96 not 106.

Calista.