108W + 312R = 3876

R = W + 3

or W = R – 3

So: 108(R-3) + 312R = 3876

108R + 312R – 324 = 3876

420R = 4200

R = 10 (minutes)

Distance 3,120 meters.

This is an example problem. You can do the others. Set up the two simultaneous equations, and solve.

1. X + X + 3 = 25 or 2X+3=25 , Solve for X

The value of X is the smaller number and X+3 is the larger.

2. 2X + 3Y = 15 and X+5 = Y

therefore you can replace Y in the first equation with X-5, so..

2X + 3(X+5) = 15 or 2X + 3X + 15 = 15 or 5X + 15 = 15

X equals the smaller value and X+5 is the Y or the larger number.

1. L=3+S, L+S=25, so 3+2S=25 and put that answer in for S in the 1st equation

2. S=L-5, 2S+3L=15, so 2(L-5)+3L=15 and put that answer in for L in the 1st equation

3. $30.24= c+(.08c), c=The cost of the shirt. (.08c)= The tax on the shirt.

4.R=3+W, 108W+312R= 3876,

so 108W+312(3+W)=3876 and put the answer in for W in the first equation. Then take that number times 312 to get the distance.