Asher runs 80 metres for 5 times. The average time taken for his first three runs is 16.4 seconds. He aims to have an average timing of 13.9 seconds for his five runs.
- What is the average time he needs to take for his 4th and 5th run in order to achieve his aim?
- If he runs 4 seconds faster in one of the five runs, what would be his average time for the five runs?
(a)
Total timing for first three runs
= 3 x 16.4
= 49.2 s
Total timing needed if the average is to be 13.9 s
= 13.9 x 5
= 69.5 s
Total timing for last two runs to achieve his aim
= 69.5 - 49.2
= 20.3 s
Average timing for last two runs
= 20.3 ÷ 2
= 10.15 s
(b)
New average
= (69.5 - 4) ÷ 5
= 13.1 s
Answer(s): (a) 10.15 s; (b) 13.1 s