The table shows the time taken by Paul to run 100 metres during his training sessions. After 3 attempts, Paul wanted to improve his average time taken by 0.5 seconds by running faster in the 4
th attempt. How fast should he run in the 4
th attempt in order for him to make the improvement?
Attempt |
1st |
2nd |
3rd |
4th |
Time taken (in seconds) |
17 |
25 |
18 |
? |
Total time that Paul took for the first 3 attempts
= 17 + 25 + 18
= 60 s
Average time that Paul took for the first 3 attempts
= 60 ÷ 3
= 20 s
New average time that Paul took for the 4 attempts
= 20 - 0.5
= 19.5 s
Total time that Paul took for the 4 attempts
= 4 x 19.5
= 78 s
Time that Paul should run in the 4
th attempt in order for him to make the improvement
= 78 - 60
= 18 s
Answer(s): 18 s