Write that as 7x. Writing it as x7 could lead to confusion. 7*x would be OK.
Distance to travel = 20 m.
Let us determine the time, t, that each participant took to complete 20 m.
Barbara:
Average speed = (3 m)/(2 s) = 1.5 m/s
t = 20/1.5 = 13.3 s
Mark:
t = 5 s
Carlos:
y = x + 1
where
y = 20 m
x = time, t
Therefore
t =x = y - 1 = 20 - 1 = 19 s
Summary:
Barbara: 13.3 s
Mark: 5 s
Carlos: 19 s
Answer:
The winner is Mark
3×2=692047 82837=284749×2484r133.e9274
Multiply the numerator and denominator by the whole number. you'll most likely get an improper fraction though.