Mrs Lee's restaurant used 45 l of oil in a day. Mrs Kim's restaurant used 10 l more oil. What was the total volume of oil used?

To find the total volume of oil used by both restaurants, we first need to determine how much oil Mrs. Kim's restaurant used. Mrs. Lee's restaurant used 45 liters of oil. Since Mrs. Kim's restaurant used 10 liters more, we can calculate the amount of oil used by Mrs. Kim's restaurant as follows: \[ \text{Oil used by Mrs. Kim} = 45 \, \text{l} + 10 \, \text{l} = 55 \, \text{l} \] Now, we can find the total volume of oil used by both restaurants: \[ \text{Total oil used} = \text{Oil used by Mrs. Lee} + \text{Oil used by Mrs. Kim} = 45 \, \text{l} + 55 \, \text{l} = 100 \, \text{l} \] Therefore, the total volume of oil used by both restaurants is **100 liters**.