Question

The student council held a car wash to raise 200$ for the childrens hospital. In the first hour, they washed 2 cars. Each hour after that, the number of cars they washed increased by 2. How many cars did they wash by the end of 6 hours.

Answer 1

Number of cars washed at the 6th hour = 12 cars

Sum of all cars washed in 6 hours = 42 cars

Explanation:

First term, a = 2 cars

Common difference, d = 2 cars

6th term = a + 5d

= 2 + 5(2)

= 2 + 10

= 12 cars

Sum of the 6th term = n/2{2a + (n-1) d}

= 6/2{2*2 + (6-1)2}

= 3{4 + (5)2}

= 3{4 + 10}

=3(14)

= 42 cars