Work out the value of x Ps I would appreciate if you showed me how to work it out

Thank you

15m is what percent of 60m; 3m; 30m; 1.5 km? the last one is km not m

Aswimming pool had 2.5 million liters of water in it. some water evaporated, and then the pool only had 22 million liters of water in it. what percent of the water evaporated?

Asource of laser light sends rays ab and ac toward two opposite walls of a hall. the light rays strike the walls at points b and c, as shown below: what is the distance between the walls?