A zebra and a giraffe are having a race, 300 yards from a row of trees (the starting line) to the edge of a stream (the finish line). When they start evenly, the zebra wins the race by 50 yards.They decide to race again, but in the second race the zebra has to start 50 yards behind the row of trees (350 yards from the finish line), while the giraffe starts at the usual starting line. The zebra and the giraffe always run at the same speeds from race to race. Who wins the second race? Explain your reasoning.

Respuesta :

A zebra and a giraffe are having a race, 300 yards from a row of trees (the starting line) to the edge of a stream (the finish line). When they start evenly, the zebra wins the race by 50 yards.

They decide to race again, but in the second race the zebra has to start 50 yards behind the row of trees (350 yards from the finish line), while the giraffe starts at the usual starting line. The zebra and the giraffe always run at the same speeds from race to race. Who wins the second race? Explain your reasoning.

we have that

The speed is equal to divide tthe distance by the time

speed=d/t

t=d/speed

The zebra and the giraffe always run at the same speeds from race to race.

so

Race 1

Zebra ------> t=300/speed1

giraffe ----> t=(300-50)/speed2 -----> t=250/speed2

where t is the finishing time of the zebra

equate both equations

300/speed1=250/speed2

300/250=speed1/speed2

1.2=speed1/speed2

speed1=1.2speed2

that means ----> the spped of the zebra is 1.2 times the speed of the giraffe

Race 2

Zebra ----> t1=350/(1.2speed2) ------> t1=292/speed2

Giraffe ----> t2=300/speed2 ------> t2=300/speed2

compare the times

t1 < t2

that means

the zebra wins the race 2