Answer:
Carlos has practiced piano for [tex]\frac{29}{20}=1\frac{9}{20}[/tex] hours.
Carlos needs to practice [tex]\frac{11}{20}[/tex] hours.
Step-by-step explanation:
We have been given that Carlos wants to practice piano 2 hours each day. He practices piano for 3/4 hour before school and 7/10 hour when he gets home.
First of all, we will find piano practiced before school and after school by adding both amounts as:
[tex]\frac{3}{4}+\frac{7}{10}[/tex]
Make a common denominator:
[tex]\frac{3*5}{4*5}+\frac{7*2}{10*2}[/tex]
[tex]\frac{15}{20}+\frac{14}{20}[/tex]
Add numerators:
[tex]\frac{15+14}{20}[/tex]
[tex]\frac{29}{20}[/tex]
Therefore, Carlos has practiced piano for [tex]\frac{29}{20}[/tex] hours.
Now, we will subtract [tex]\frac{29}{20}[/tex] from 2 find number of hours Carlos needs to practice to reach his goal.
[tex]2-\frac{29}{20}[/tex]
[tex]\frac{2*20}{20}-\frac{29}{20}[/tex]
[tex]\frac{40}{20}-\frac{29}{20}[/tex]
[tex]\frac{40-29}{20}[/tex]
[tex]\frac{11}{20}[/tex]
Therefore, Carlos needs to practice [tex]\frac{11}{20}[/tex] hours before going to bed in order to meet his goal.