Question

Mr. Malone used 40 pounds of insecticide to cover 1,760 square feet of lawn and 60 pounds to cover an additional 2,640 square feet. how many pounds of insecticide would Mr. Malone need to cover his whole lawn of 4,480 square feet?

Answer 1

Using the given information, we are able to setup proportion:


`(100)/(4400)=(x)/(4480) \\4400x=100\cdot4480 \\x=(100\cdot4480)/(4400)=(1120)/(11)=101.\overline{81}\approx102lb`

Answer 2

101.8182 pounds.

Explanation:

He used 40 pounds of insecticide to cover 1760 square feet of lawn and 60 pounds to cover an additional 2640 square feet. So,

1760 + 2640 = 4400 square feet of lawn with 40+60 = 100 pounds of insecticide. Then, his whole lawn is 4480 square feet andn he already covered 4400, so he need to cover 4480 - 4400 = 80 square feet more.

Now, one of the data given we can do a proportion:

40 pounds to 1760 square feet =
`(40pounds)/(1760ft^2)`

x pounds to 80 square feet =
`(xpounds)/(80ft^2)`

`(40pounds)/(1760ft^2)=(xpounds)/(80ft^2)`

`xpounds*1760ft^2 = 80ft^2*40pounds`

`xpounds = (80ft^2*40pounds)/(1760ft^2)`

`xpounds = (3200pounds)/(1760)`

`x = 1.8182 pounds.`

Then, to cover his whole lawn of 4480 square feet he needs 100+1.8182 = 101.8182 pounds of insecticide.