What is the largest parcel that weighs 5KG could be if the price for sending it is less than three dollars

Complete question:

A postage company delivers parcels which are in the shape of a cuboid. The length of every  side of the parcel must be a whole number of centimeters. The price in cents is determined by  multiplying the weight of the parcel (to the nearest kilogram) by 30 and then adding on 20 times  the length of the longest side of the parcel.

What is the largest parcel that weighs 5KG could be if the price for sending it is less than three dollars

7cm long

Step-by-step explanation:

Given

Let

--- in cents

From the question, p is calculated as:

Required

Calculate the largest parcel when weight = 5 kg and price < $3

Convert price to cents

The formula:  becomes

Collect like terms

Divide both sides by 20

Since the length must be in whole numbers, then the largest parcel is 7cm long