They are both correct in their computation
(28.5-28.5(.3))+.1(28.5-28.5(.3))=$21.945
28.5(.7)(1.1)=$21.945
And since they each have $22 to spend, they have enough to purchase the book.
On Saturday, 4/4 of the amount of people attended. On Friday, 3/4 of the amount on Saturday attended. We have 7 parts (3 from Friday and 4 from Saturday).
840/7 = 120.
Thus, 360 people attend on Friday and 480 on Saturday.
The formula for solving the problem is as follow:
an = a1 + (n - 1)d
Where:
n = number of figure in the sequence = 4
d = difference between successive number =?
a1 = -1
a4 = 59
Insert the given values into the formula,
59 = -1 + (4 - 1)d
59 = -1 + 3d
59 + 1 = 3d
60 = 3d
d = 60/3 = 20
Therefore, d = 20. This implies that, there is a difference of 20 between successive numbers.
The number sequence is as follow:
-1, 19, 39, 59.
