2 people of Taro and Jiro did footrace (running race).
When both of 2 people ran through 100m, Jiro did a goal 4 seconds later than Taro.
Next when Taro started from the point 25m after Jiro, 2 people made the goal at the same time.
Noted that 2 people start at the same time and run with a fixed speed respectively.
(1) Express the speed ratio of Taro and Jiro in the ratio of the least integer.
(2) How many m per second was the speed of Taro?
Answer
(1) 5 : 4
(2) 6.25 m/s
Solution
(1) Because Taro runs 125 m and Jiro runs 100 m in the same time, the speed ratio of Taro : Jiro = 125 : 100 = 5 : 4.
(2) Because the time ratio which two persons run 100 m is to be inverse ratio of the speed ratio, it'll be Taro : Jiro = 4 : 5. 5 - 4 = 1 which is the difference of the ratio is equivalent to 4 seconds.
Time when it takes for Taro to run 100 m is 4 × 4 = 16 seconds.
Therefore speed of Taro is 100/16 = 6.25 m/s.
