Afactory produced 150 tons of steel in one year. the next year, the output increased to 180 tons. what is the percentage increase in the output?

The amount of increase is  (180 - 150)  =  30 tons.

The increase as a part of the original amount is  30/150  =  0.2

To change a decimal into a percent,
move the decimal point 2 places that way  ===> .

                     0.2  =  20%