Can somebody answer this and can you show your work!

Two sides of a triangle mesure 20cm and 30cm. what is the measure of the third side

Jonathan can type 20 documents in 40 minutes ,and susan can type it in 30 minutes and jack can type it in 24 minutes working together ,how much time will it is take them type the same document

(01.04 lc)multiply 1 over 6 multiplied by negative 1 over 2. negative 1 over 3 negative 1 over 12 1 over 12 1 over 3