Larry has 4-cent stamps and 19-cent stamps, which he can combine to produce various amounts of postage. For example, he can make 80 cents by using four 19-cent stamps and a 4-cent stamp. However, there are some amounts of postage he can't make exactly, such as 10 cents.
What is the largest number of cents that Larry CANNOT make exactly from a combination of 4- and/or 19-cent stamps?
Explain how you know your answer is correct. (You should explain two things: why Larry can't make the amount of your answer, and why he CAN make any bigger amount.)
Largest number you CANNOT make = 53
(1, 2, 3, 5, 6, 7, 9, 10, 11, 13, 14, 15, 17, 18, 21, 22, 25, 26, 29, 30, 33, 34, 37, 41, 45, 49, 53) >Numbers you CANNOT make = 27.
ALL numbers above 53 you can make. Numbers that you can make are ALL multiples of 19 and 4 or combinations thereof. All numbers that you cannot make fall outside of those multiple combinations.
