Question

Pencils come in packages of 10. Erasers come in packages of 12. Jimmy wants to purchase the smallest number of pencils and erasers so that he will have exactly 1 eraser per pencil. How many packages of pencils and erasers should Jimmy buy?

Answer 1

Answer:

Here are two ways to find the LCM (Least Common Multiple) of two numbers:

 

[1] list all of the multiples and choose the least common number

of 10:   10  20  30  40  50  60  70  80  90  100

of 12:   12  24  36  48  60  72  84  96

 

[2] find a number that shares all the prime factors of the two numbers

(thus, is divisible by both of the numbers)

prime factors of 10:    2, 5

prime factors or 12:    2, 2, 3

LCM = 2*2*3*5 = 60

Answer 2

jasonfrancis1811420 Agreed