Question

Please help me :(

Answer 1

Answer:

The limits between which T lies is 273 hours 30 mins < T < 242 hours 30 minutes

Step-by-step explanation:

The number of hours Angharad sleeps each night = 8 hours ± 10 minutes

The actual time Angharad sleeps each night = 8 hours ± 5 minutes

Which gives the maximum time Angharad sleeps = 8 hours 5 minutes = 485 minutes per night

The minimum time Angharad sleeps = 7 hours 55 minutes = 475 minutes

The number of days in the month of November = 30 nights

The maximum time in minutes Angharad sleeps in November, $T_{max}$ = 30 nights × 485 minutes/night = 14,550 minutes = 242.5 hours = 242 hours 30 minutes

The minimum time in minutes Angharad sleeps in November, $T_{min}$ = 30 nights × 475 minutes/night = 14,250 minutes = 237.5 hours = 237 hours 30 minutes

Therefore, we have, the limits between which T lies given as follows;

273.5 hours < T < 242.5 hours.

Answer 2

Answer:

235 ≤ T ≤ 245

Step-by-step explanation:

(8 hours per night x 30 nights) = 240 hours

The deviation from 8 hours per night is as much as 10 minutes per night.  

Over 30 nights, the total deviation can be as much as (30 x 10 minutes) = 300 minutes = 5 hours.

So T can be as much as (240 + 5) = 245 hours, or as little as (240 - 5) = 235 hours.

In inequality form,

235 ≤ T ≤ 245