Odd numbers take the form
, where
is an integer. When
, the last odd number would be 799. So we're adding

By reversing the order of terms, we have

and we can pair up terms in both sums at the same position to write

so that we are basically adding 400 copies of 800, and from there we can find the value of the sum right away:

###
We could also make use of the formulas,


We have

Answer:
36.67 [mile/hour].
Step-by-step explanation:
1) use the formula: V=S/t, where S - entire jorney, v - average speed (required to calculate), t - elapsed entire time.
2) according to the formula above S=50+60=110 miles; t= 50/40 + 1.75=1.25+1.75=3 hours.
3) after the substitutuion 110 and 3 into the formula above:
v=110/3≈36.67 miles/h.
Answer:
Divide 63/9=7
7*2= (the number of teachers) 14
There are 14 teachers for 63 students.
Basically, just find a common denominator. The LCD of 8 and 10 is 40 and that is divisible by 5, too. So the answer is 40 days.
The domain of the relation is 7,13 and the range of the relation is 4,20. I hope this helps.