Let the variable be the cost of the lunch: x
so they bought 5 lunches: 5x
deserts are cheaper than lunches; they cost:
x-5.25
So together they paid:
5x+3*(x-5.25)=60.25
(we know how much they paid, so we can make an equation)
Let's remove the bracket:
5x+3*x-15.75=60.25
8x-15.75=60.25//we add 15.75 to both sides:
8x=76
and divide by 8:
x=9.5
So each lunch costs 9.5 dollars!