You plan on moving and offer to buy lunch for any friends that . you buy the sandwiches at subway for $30 that included 6 tuna sandwiches and 6 turkey sandwiches. later at night , you buy more sandwiches and buy 4 tuna sandwiches and 8 turkey sandwiches for $30.60. what is the price of each sandwich ?

You buy the sandwiches at subway for $30 that included 6 tuna sandwiches and 6 turkey sandwiches

Let x be the price of tuna sandwiches

and y be the price of turkey sandwiches

6x + 6y = 30

Divide both sides by 6

x + y = 5 equation 1

you buy more sandwiches and buy 4 tuna sandwiches and 8 turkey sandwiches for $30.60.

4x  + 8y = 30.60 equation 2

x + y = 5

so y = 5 -x

Now plug in 5-x for y in second equation

4x  + 8y = 30.60

4x  + 8(5 - x) = 30.60

4x + 40 - 8x = 30.60

-4x + 40 = 30.60

Subtract 40 on both sides  

-4x = -9.4

divide both sides by -4

x = 2.35

We know y = 5 -x

y = 5 - 2.35 = 2.65

the price of tuna sandwiches= $2.35

the price of turkey sandwiches= $2.65