Answer
Incorrect
Explanation
Unpack the problem:
Let the distance round the track to be X.
Speed is the ratio of distance to time.
Robert run a distance of (1/2)x
Elaine run a distance of (3/4)x
Make a plan:
Finding the speed of each.
Compare their speeds to determine who ran faster than who.
Solution:
Robert's speed =(1/2)x/(5/6)
=1/2×6/5x
= (3/5)x
= 0.6x
Elaine's speed = (3/4)x/(9/10)
= (3/4)×(10/9)x
= (5/6)x
= 0.83333x
Elaine ran faster than Robert.
Look back and explain:
0.83333x > 0.6x
Elaine's speed is higher than Robert's speed.
This shows that Elaine ran faster than Robert.
