Marc and Aki are building hot wheels tracks. Marc has 4-inch pieces to make his track, and Aki has 10-inch pieces to make his track. How long will their tracks be when they are first the same length?
The lengths of Marc's tracks are multiples of 4 inches: 4, 8, 12, 16, ...
The lengths of Aki's tracks are multiples of 10 inches: 10, 20, 30, 40, ...
To find the first time their tracks are the same length, we need to find the least common multiple (LCM) of 4 and 10.
The prime factors of 4 are 2 and 2.
The prime factors of 10 are 2 and 5.
Multiplying these prime factors together, we get the LCM = 2 x 2 x 5 = 20.
Therefore, their tracks will be the same length when they both have 20 inches of track.