Answer:
Ann would need 3 h to complete the remainder of the Job.
Step-by-step explanation:
Step 1.
The "speed" that each girl has to do the work is determined as:
- Tina:
, it means that Tina complete one twelveth of the job each hour. - Ann:
, it means the Ann completes one eighth of the job each hour.
Step 2.
The amount of work done by Tina in 9 hours, is obtain multiplying by the "speed" calculated in step 1:
Amount of work done=
. It means that <em>Tina completes two thirds of the work in 9 h.</em>
Step 3.
The remaining job is calculated as
. It means that <em>still remains is one third of the job to be completed</em>.
Step 4.
The time required for Ann to complete the job is calculated dividing the remaining of the job by the "speed" of Ann to do the job.
. It means that <em>Ann would complete the job in another 3 hours</em>.
ANSWER

EXPLANATION
Method 1
Vertically opposite angles are equal, therefore

This implies that,

We simplify to get,

Dividing through by 3 gives,

Also,

This implies that,

We simplify the right hand side to get,

We divide both sides both sides by 2 to get,



Method 2
Angles on straight line sums to 180°.

This implies that,




Also,






Answer:
It's legit just 5.9600000000000000000000000000000000000000000.
The correct answer is 21 and 9. 21+9=30 and 21-9=12. Hope this helps.