I gonna resolve this one just to explain what is mdc

A seamstress has four spools of ribbon measuring 164 m, 136 m, 112 m and 84 m respectively. She needs to cut these ribbons into pieces of equal length, each piece being as long as possible. The maximum number of pieces obtained and the length, in meters, of each piece will be, respectively,

A) 124 e 6.

B) 124 e 4.

C) 132 e 4.

D) 132 e 6.

E) 184 e 8. 

This is where the mdc applies, the maximum common divisor which is that I divide all the numbers by divisors common to all of them, explaining it more explicitly if there is no number by which all of them are not divisible then the mdc is 1

164,136,112,84]4 are all divisible by 4,

     41,34,28,21] there is no other number that divides them all so it's just 4

 so 4 is the maximum common divisor, and I won't need to do any more calculations because this result on the left is already the number of parts, because you see they are divided by 4, so what do I take the whole numbers and divide by 4 for? So adding them all up 41+34+28+21 = 124

Rute Bezerra de Menezes Gondim