Compute the cost of not taking the following trade discounts: $($Use $365$ days in a year. Round the final answers to $2$ decimal places.$)$

a$.2/18,$ net $50.$

Cost of lost discount $\%$

b$.\frac{3}{16},$ net $45.$

Cost of lost discount $\%$

c$.\frac{4}{19},$ net $45.$

Cost of lost discount $\%$

d$.\frac{3}{19},$ net $145.$

Cost of lost discount

$\%$