Answer: 120 commercial vans, 60 small trucks, and 80 large trucks
Explanation: First, we will define the variables that we need to solve the problem. In this case the question is, how many of each type of vehicle, so let
V = number of vans
S = number of small trucks
L = number of large trucks
Next, we will translate the words in the problem into mathematical statements that we can use to solve the problem, thus:
"twice as many vans as small trucks" means that:
V = 2*S
"260 new vehicles" means that:
V + S + L = 260
The last part is the cost equation which is a little more complicated:
25000*V + 50000*S + 50000*L = 10,000,000
Divide both sides of this equation by 1000, we have:
25*V + 50*S + 50*L = 10000
We start with the simplest one:
V = 2*S.
This means that wherever we see a V in the other 2 equations we can replace it with 2*S, which will leave us with 2 equations in 2 unknowns
(2*S) + S + L = 260 ==> 3*S + L = 260
25*(2*S) + 50*S + 50*L = 10000
==> 100*S + 50*L = 10000
Now we can solve the top equation for L to get L = 260 - 3*S
and substitute this value for L into the bottom equation
100*S + 50*(260 - 3*S) = 10000
100*S + 13000 - 150*S = 10000
-50*S = -3000
S = 60
Once we have one of the answers then plug in back in to previous equations to find the others
L = 260 - 3*S = 260 - 3*(60)
= 260 - 180 = 80
V = 2*S = 2*(60) = 120
So they can buy 120 commercial vans, 60 small trucks, and 80 large trucks