If a donut shop sold 150 donuts in 6 hours, and each hour they sold 6 more donuts than the previous hour. What's the total number of donuts they sold in the first 3 hours?

36 doughnuts.

hour one: 6

hour two: 12

hour three: 18

150 divided by 6 is 25 so that’s the first hour, the second hour is 25 plus another 6 and that is 31, then the third hour is 31 plus 6 which equals 37. So, 25+31+37 = 93, and that means they sold 93 donuts in 3 hours