Answer:
Cost price of the burger = $4.15
Step-by-step explanation:
Given data:
3 burgers were ordered
3 medium fries were ordered
Total order cost 17.55
Let the price of the burger be X
Let the price of the medium fries be Y
<em>Equation for the total sale will be </em>3X + 3Y = 17.55 <em>(equation 1)</em>
<em>from this statement 'The price of a burger is .75 more than two times the price of medium fries.' </em>
X - 2Y = 0.75 <em>(equation 2)</em>
<em>There are now two equations and two unknowns, a simultaneous equation is solved to find the cost of the burger.</em>
<em>Many methods can be used to solve these equations but in this case substitution will be used</em>
<em>From equation 2 </em>
X = 0.75 + 2Y<em> (equation 3)</em>
<em>Substituting equation 3 into equation 1</em>
3(0.75 + 2Y) + 3Y = 17.55
2.25 + 6Y + 3Y = 17.55
6Y + 3Y = 17.55-2.25
9Y = 15.3
Y = 1.7
<em>Substituting Y into equation 3</em>
X = 0.75 + 2Y
X = 0.75 + 2(1.7)
X = 0.75 + 3.4
X = 4.15
Therefore the cost price of the burger is $4.15
