there are several ways to do problems like this. the shorter way is to set and solve for . this gives you the decimal value form of the percentage. multiply by 100 to get the percentage.

as you may have trouble seeing why that works, another method is to first find the difference.

so we increased by 83. now the task is to find what percentage of 102 is 83

that's given by

the second question can be done in a similar manner