If 12 +2 =2 orderly what is 6 +3 orderly​

Awater holding tank measures 105 m long, 50 m wide, and 8 m deep. traces of mercury have been found in the tank, with a concen- tration of 60 mg/l. what is the total mass of mercury in the tank? answer in units of kg.

Due to bad planning, two of the local schools have their annual plays on the same weekend. while 457 people attend one, and 372 attend the other, only 104 people were able to attend both. how many people went to at least one play?

Julie was able to walk 16 km through the zoo in 6 hours. how long will it take her to walk 24 km through the zoo?