Dennis sister charges 550 per hour before 9 p. m. for babysitting and $8 per hour after 9 p. m. she finished babysitting at 11 p. m. and earn $38 at what time did she begin babysitting

Since we know what time Dennis' sister finished babysitting, we can calculate how much money she's made since 9p.m. Between 9 and 11 is 2 hours, so we know she made $16 ($8 per hour x 2 hours).

That means she made $22 before 9p.m. ($32 total - $16 made past 9p.m.)

So, you just need to figure out how many hours $22 is worth and subtract that number of hours from 9p.m. That will get you to the starting point of babysitting.

$22 / $5.50 = 4     so we know that $22 is 4 hours' worth of babysitting.

9p.m. - 4 hours is 5p.m., so we know that Dennis' sister started babysitting at 5p.m. 

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Okay so for every triangle has three angles that always add up to 180 degrees. and to tell the difference between whether they are secure, right or obtuse is that acute: has one angle that is less than 90 degrees. right triangle means there is at least one angle that is exactly 90 degrees. and an obtuse angle has an angle that is bigger than 180 degrees. i’ll do #13 as an example: 13. 40 and 50 so if every triangle has 180 degrees 40+50= 90 degrees then180-90= 90 degrees so the third angle is 90 degrees and because this triangle has a 90 degree angle it means it is a right triangle