Question

15 postcards, 10 envelopes, and a notepad cost 1 dollar and 68 cents. The envelope is 8 times cheaper than the notepad and 2 cents more expensive than the postcard. What is the price of the postcard, the envelope and the notepad?

Answer 1

15 postcards, 10 envelopes, and a notepad cost------------------- 1.68 dolars

Postcards------------x

Envelopes------------y

Notepad--------------z

15x+10y+z=1.68

Y=z/8 y=0.02+x

Z=8y x=y-0.02

15(y-0.02)+10y+8y=1.68

15y-0.30+18y=1.68

33y=1.98 y=0.06

Z=8*0.06=0.48

X=0.06-0.02=0.04

Costs

Postcards------------0.04 dolars/ 4 cents

Envelopes------------0.06 dolars/ 6 cents

Notepad--------------0.48 dolars/ 48 cents