Let
x -----> ordered sandwiches
y ----> extra sandwiches
Part a
we have
x=20
y=3
ratio=x/y
substitute
ratio=20/3
Part b
we have
x+y=184 -----> x=184-y ----> equation 1
x/y=20/3 -----> x=(20/3)y ----> equation 2
equate equation 1 and equation 2
184-y=(20/3)y
solve for y
(20/3)y+y=184
(23/3)y=184
y=184*3/23
y=24
Find out the value of x
x=184-24
x=160
therefore
number of sandwiches is 160
