Four friends have different numbers of cows on their farms. jorge has 3 times as many cows as carla. marcus has half as many cows as jorge. dominique has 2 less than 4 times as many cows as carla. how many cows do they each have if they have a total of 169 cows?

Let us say:

x = Jorge

y = Carla

z = Marcus

a = Dominique

We are given that:

x = 3y                                                    --> 1

z = 0.5x                                                 --> 2

a = 4y – 2                                             --> 3

x + y + z + a = 169                             --> 4

Substituting 1 to 2:

z = 0.5(3y) = 1.5y                              --> 5

Substituting 1, 3 and 5 to 4:

3y + y + 4y – 2 + 1.5y = 169

9.5y = 171

y = 18

Hence,

x = 3y = 3*18 = 54

z = 0.5x = 0.5(54) = 27

a = 4y – 2 = 4(18) – 2 = 70

y = 18