Hi,

A) A dealer buys 200 similar envelopes for $60. He sells them for 80 cents each.

a. How much money did he sell them all for?

200 x 80 = 16 000 cents

=> $160.00

He sold them all for $160.00.

b. What was his percentage profit?

$\displaystyle \frac{\rm{Selling\ Price - Cost\ Price}}{{\rm{Cost Price}}}\times 100$

$\displaystyle \frac{160 - 60}{60} \times 100$

$\displaystyle 166\frac23 \%$

B) Find the percentage profit:

i. Cost Price is 30 cents and Selling Price is 35 cents

$\displaystyle \frac{5}{30} \times 100$

$\displaystyle 16\frac23 \%$