MY SIS IS ASKING ME TO HELP WITH HOMEWORK AND IM DOIN MINE she’s annoyinggg T^T can anyone help her rn I can’t lol 6.36 + (2.64 + 5.27) pls help she’s literally yelling in my face

14.27

Step-by-step explanation: You always want to do parenthesis first when you do that you get 7.91. When you do that you take you answer (7.91) and add it to 6.36 and then will get 14.27 I hope this helps your sister :)

14.27

Step-by-step explanation:

Add in the parenthesis first

6.36+(7.91)

then add the rest

14.27

Answer

Average speed of the train = 90 km/h and average speed of the airplane = 360 km/h.

Explanation:-

If speed of train = x then the  speed of airplane = 4x km/h and we have the 2 equations

x = 1440 / (t + 12)                               (t = time taken by the train)

4x = 1440 / t(1)       (t = time taken by train)

Multiply the first equation by 4:-

4x = 5760 / (t + 12)(2)  

Combining equations (1) and (2):-

1440 / t =  5760 / (t + 12)

Cross multiplying:-

5760t = 1440t + 17,280

4320t = 17,280

t = 17280/4320

t = 4 hours

speed of train = 1440/ (4 + 12) = 90 km/h and speed of plane = 4*90 = 360 km/h.