Answer:
Dave worked 60 hours.
Step-by-step explanation:
Let's assume that Dave worked a total of
hours.
Since Kate worked 5 hours less than Dave: 
And Sarah worked 10 more hours than Dave: 
Combined, the three siblings worked 185 hours.

Dave worked 60 hours,
Kate worked 55 hours and Sarah worked 70 hours.
To check:
55 + 60 + 70 = 185 hours
Hey!
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Find the zero term:
Plug in 0 for n.
a = 8 + 3(0 - 1)
a = 8 + 3(-1)
a = 8 + (-3)
a = 5
Answer: 5
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Find the first term:
Plug in 1 for n.
a = 8 + 3(1 - 1)
a = 8 + 3(0)
a = 8 + 0
a = 8
Answer: 8
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Find the 40th term:
Plug in 40 for n.
a = 8 + 3(40 - 1)
a = 8 + 3(39)
a = 8 + 117
a = 125
Answer: 125
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Hope This Helped! Good Luck!
Answer:270
Step-by-step explanation:180/2=90
90*3=270
Hope this helps :)