It is given that Owen and Eva spent the same amount, which means that the amount that Owen spent is a multiple of 10. So in order to find how muchOwenspent,youhavetofindLCMof10and14 10 :
LCM of 10 = 2, 5
LCM of 14 = 2, 7
LCM of 10&14 = 2×5×7
= 70
14 × 5 copies = 70 cents
Next, we have to find how many copies did Eva spent using 70 cents because both of them spent the same amount :
10 cents = 1 copy
70 cents = 1 copy × 7
= 7 copies
Lastly, Eva has 7 copies and Owen has 5 copies so the difference between them is 2 copies.