The salary seems rather large so we'll use S for salary, T for taxes, P for pension and M for medical. This is how to do the calculation: S-T-P-M is the take home pay, or we can write this S-(T+P+M). The percentage of her salary she keeps as take home pay is 100*(S-(T+P+M))/S. The deductions are 100*(T+P+M)/S as a percentage. These two percentages should add up to 100%. In this problem T+P+M=$2100. S appears to be $1,000,300, but may really be $10,003.00. Let's assume the latter figure: 100(10003-2100)/10003=79%. And the deduction percentage is 21%.