The table shows the time taken by Japheth to run 100 metres during his training sessions. After 3 attempts, Japheth wanted to improve his average time taken by 1.4 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 |
15 |
22 |
? |
Total time that Japheth took for the first 3 attempts
= 17 + 15 + 22
= 54 s
Average time that Japheth took for the first 3 attempts
= 54 ÷ 3
= 18 s
New average time that Japheth took for the 4 attempts
= 18 - 1.4
= 16.6 s
Total time that Japheth took for the 4 attempts
= 4 x 16.6
= 66.4 s
Time that Japheth should run in the 4
th attempt in order for him to make the improvement
= 66.4 - 54
= 12.4 s
Answer(s): 12.4 s