Question

The choir at wise middle school was preparing for their Hispanic concert. While rehearsing their opening song they noticed it took 48.7 seconds to sing it.They felt it was too long and sang it again taking off 2.9 seconds from the original time. The third time they sang it they were able to take an additional 0.47 seconds off their time. How long did it take the choir to sing the song the third time?

Answer 1

45.88 seconds

Explanation:

`t_1` = Time taken to sing the fist time =
`48.7\ \text{s}`

Time taken to sing the second time was
`2.9\ \text{s}` less than the first time so

`t_2=t_1-2.9\\\Rightarrow t_2=48.7-2.9\\\Rightarrow t_2=45.8\ \text{s}`

Time taken to sing the third time was
`0.47\ \text{s}` less than the the second time

`t_3=t_2-0.47\\\Rightarrow t_3=45.8-0.47\\\Rightarrow t_3=45.88\ \text{s}`

So the time it took the choir to sing the third time was 45.88 seconds.