The answer is 93
If we sorted out the number of each hours, the sequence will look like this
57 _ 69 _ 81 _ x _ 105
(in which x is the fourth hour of work)
We can see from the sequence that each hours, the mailman add additional 12 letters.
(69 - 57 = 12)
(81 - 69 = 12) . . . . proof
So, the amount of letters on the fourth hour would be:
81 letters + 12 letters = 93 Letters
5 is correct and 6 is 1/2
(x+2y)(x-5y)
do foil method:
x^2-5xy+2xy-10y^2
simplify x^2-3xy-10y^2,
so d is correct.
I dont know for a fact but it could be 0.70710678118 but im not sure
The angle that is obtuse is 1, because it is greater than 90°.
Hope this helps and have a nice day:)
