Let’s make a pair of equations, one for what you ordered, one for what your friend ordered. We’ll have x represent soft tacos and y represent burritos.
Your order: 3x + 3y = 11.25
Your friend’s order: 4x + 2y = 10
The first thing I gather using the information above is that burritos are more expensive then tacos, right? Your order is more expensive, with 1 less taco and 1 more burrito than your friend’s. But now we need to find out just how much more burritos cost.
To do that, pick an equation and simplify it for either x or y. I’ll choose the second equation, because it has a simpler answer. Let’s see what y equals for that one. 2y = 10 - 4x y = 5 - 2x
Burritos cost 5 minus the cost of two tacos. Just replace y with this in our other equation. 3x + 3(5-2x) = 11.25 Use the distributive property. 3x + 15 - 6x = 11.25 15 - 3x = 11.25 -3x = -3.75 3x = 3.75 One taco costs $1.25 It’s easy to find out what the other variable equals once you have one already. Just pick either of the equations and know how much a taco costs. I’ll jump back to the second one.
4(1.25) + 2y = 10 5 + 2y = 10 2y = 5 y = 2.5
As predicted, burritos cost more. One taco costs $1.25. One burrito costs $2.50. With problems like these, you can always double-check the answers if you’d like. Just plug in the numbers.
Since a square has all equal sides, this would mean the the all the other sides are 20 as well. To get the area, you would just multiply 20 by 20 to get 400. :)
