Answer:
let k represents the kumquat weight(in pound) and p represents the Asian pears weight respectively.
As per the given conditions,
The grocery store sells kumquat for $ 4.50 a pound
⇒ for 1 pound
$4.50
then, in k pound =

similarly,
The Asian pears for $3.75 a pound
⇒ for 1 pound
$3.75
then, in p pound =

Standard form of the equation is in the form of Ax + By = C:
The weight of kumquat k and Asian pears p that customer could buy with $ 16,
then the standard form of equation is: 4.50k +3.75p = 16