The rate (in liters per minute) at which water drains from a tank is recorded at half-minute intervals. Use the average of the left- and right-endpoint approximations to estimate the total amount of water drained during the first 3 min.

0 | 0.5 | 1 | 1.5 | 2 | 2.5 | 3 | |

l/min | 44 | 42 | 40 | 38 | 36 | 34 | 32 |

Answer: