+0  
 
0
152
2
avatar

In a theater, there are 20 chairs in the first row, each row has 4 more chairs than the previous row, and there are 15 rows. How many chairs are there in the theater?

 Aug 24, 2020
 #2
avatar
0

Use AP formula to sum them up:

 

Sum = 15/2 * [2*20 + 4*14 ]

Sum = 7.5 * [40   +     56 ]

Sum = 7.5 *      96

Sum = 720 chairs in the theater.

 Aug 25, 2020

11 Online Users

avatar
avatar