From the question, we have the following information available;
Note that this is equivalent to 178 cents when reduced to its lowest form.
Also we are told that Scott purchased 43-cent and 7-cent stamps. That implies that he spent the exact amount to purchase stamps without change (no remainders).
178 is not a multiple of 43, which means he couldnt have bought all 43-cent stamps even if he wanted to.
172 is a multiple of 43 (that is, 43 times 4 = 172). However, if he bought 4 stamps for 172 cents then he would have just 6 cents as the remainder.
Hence, he could opt to buy 3 of the 43-cent stamps, and that would be;
Therefore, if he spends 129 cents on stamps, he would have a remainder of 49 cents.
Note also that 49 is a multiple of 7. That means he can use the remainder to purchase 7-cent stamps as shown below;
This shows that he buys the stamps in the following order;
ANSWER:
3 -- 43 cent stamps
7 -- 7-cent stamps