Frank purchased postcards for $2 each and ornaments for $7 each. If he spent a total of $42 on 11 souvenirs, how many ornaments and how many postcards did Frank purchase?

Answer 1

2P + 7O = 42

P + O = 11 multiply by 2 and subtract from the 1st equation

2P + 2O = 22

5O = 20 divide by 5

O = 4 ornaments

P = 11- 4 = 7 post cards