+595 A restaurant has a profit of $1,300 in January. The profit will increase by $150 each month for 11 months.
What will the total profit be over the 12-month period?
The first row of a section in a stadium has 10 seats. The second row has 11 seats. The third row has 12 seats. This pattern continues and the section has 24 rows.
How many seats are in this section?
+129852 Note that the sum of the first n positive integers is
n (n + 1) / 2
For the first one we have this :
Total Profit =
1300 + 150 ( 1 + 2 + 3 +....+ 10 + 11) =
1300 + 150 [ 11 (12)] /2 =
1300 + 75 * (132) =
$11200
The second is easier
The number of seats is given by
(33 + 10) * (n/2) where n is the number of rows = 24 and the last row has 33 seats
(43) (24/2) =
43 * 12 =
516 seats
