Lamar watched his little sister while his mom was busy. He played blocks with her for 15 minutes peek-a-boo for 5 minutes and trains for 13 minutes. His mom came back to put his sister down for a nap at 2:15. What time did Lamar start watching his sister? Show your work

1:42

Step-by-step explanation:

Add the amount of time he watched his sister: 15+5+13=33

Subtract the end time by the amount of time he watched his sister: 2:15-33

-To do this I first I subtracted 15 minutes from the 33 to the 2:15 so you are left with 2:00 and 18 mins

- now subtract 18 mins from 2:00 or 60 = 1:42

you would use (d.) the law of cosines or a^2 = b^2 + c^2 – 2bc(cos a)

, b^2 = a^2 + c^2 – 2ac(cos b), or c^2 = a^2 + b^2 - 2ab(cos c). you wouldn't use b. the law of sines as it is mostly effective when 1side and 2angles are given. a and c aren't the answer for they are the improper versions of the law of cosines. hope this is .