Question

Lily went shopping with alan. lily spent $11.20 for 3.60 kg flour and 1 kg sugar. alan spent $20 for 5 kg flour and 2.50 kg sugar. what is the price of a kilogram of flour and a kilogram of sugar respectively?

Answer 1

Write an equation system based on the problem
An equation for Lily's expense is
∴ 3.6f + s = 11.2  (first equation)
An equation for Alan's expense is
∴ 5f + 2.5s = 20   (second equation)
f stands for the price of a kilogram of flour, s stands for the price of a kilogram of sugar

From the first equation, solve for s
3.6f + s = 11.2
s = 11.2 - 3.6f

Subtitute s with (11.2 - 3.6f) in the second equation
5f + 2.5s = 20
5f + 2.5(11.2 - 3.6f) = 20
5f + 28 - 9f = 20
-4f + 28 = 20
-4f = 20 - 28
-4f = -8
f = -8/-4
f = 2
A kilogram of flour is $2

Subtitute f with 2 to find the value of s
s = 11.2 - 3.6f
s = 11.2 - 3.6(2)
s = 11.2 - 7.2
s = 4
A kilogram of sugar is $4

Answer 2

Or 1 kilogram = 2 pounds 3 ounces. To change from KILOGRAMS TO POUNDS we can multiply by 2.2. So is we have a 2kg bag of flour and we want to know what this is in pounds we can work it out like this: 2kg = 2 x 2.2lbs = 4.4lbs. A. Try these. 1) 3kg = lbs. 2) 6kg = lbs. 3) 7kg = lbs. 4) 12kg = lbs. 5) 14kg = lbs. 6(