The table shows the time taken by Fred to run 100 metres during his training sessions. After 3 attempts, Fred wanted to improve his average time taken by 0.7 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) |
25 |
16 |
19 |
? |
Total time that Fred took for the first 3 attempts
= 25 + 16 + 19
= 60 s
Average time that Fred took for the first 3 attempts
= 60 ÷ 3
= 20 s
New average time that Fred took for the 4 attempts
= 20 - 0.7
= 19.3 s
Total time that Fred took for the 4 attempts
= 4 x 19.3
= 77.2 s
Time that Fred should run in the 4
th attempt in order for him to make the improvement
= 77.2 - 60
= 17.2 s
Answer(s): 17.2 s