• Oct 8th 2007, 09:15 AM
billR2D2
A lawn is 30m by 35m. The fertilizer for the lawn is applied at 5 Ibs per 750 square feet and comes in 50 Ibs bags. How many bags are need?

note: If you know the answers can you please explain it to me in simple terms? Don't put anything complicated. Thank you.
• Oct 8th 2007, 09:32 AM
DivideBy0
Are you sure the scaling is correct? It's just that it's odd to have metres and feet (Imperial System and SI) in the same question.

Ok, assuming you mean 30 feet by 35 feet,

Then the area of the lawn is $30 \times 35=1050$ square feet

Now, since 5 pounds covers 750 square feet, 50 pounds (1 bag) will cover 7500 square feet.

Now we can use ratios to determine how many bags we need. Let x be the number of bags we need.
As you can see, the ratios of the areas of the lawn is $1050:7500$
and the ratio of the bags needed is $x:1$

Note that $1050:7500=x:1$

That is,

$\frac{1050}{7500}=\frac{x}{1}$

Now simply solve for x:

$x=\frac{1050}{7500}=\frac{105}{750}=\frac{21}{150} =\frac{7}{50}$ of a bag.
• Oct 8th 2007, 09:47 AM
billR2D2
whats with the : ?
• Oct 8th 2007, 10:09 AM
billR2D2
it's not 30feet by 35feet. It's m it says in my textbook.
• Oct 8th 2007, 11:00 AM
Sculthorp
You have to convert the feet to meters or viceversa and everything would be alot more simple.. no? Just find the conversion rate and then it's just simple math
• Oct 8th 2007, 11:13 AM
Jhevon

1 meter = 3.2808399 feet
• Oct 8th 2007, 01:50 PM
DivideBy0
Quote:

Originally Posted by billR2D2
whats with the : ?

$a:b=\frac{a}{b}$, usually only used when comparing objects.

Ratios

Replace 1050m^2 with 1050* 3.280 839 895 feet squared and continue as I did.
• Oct 9th 2007, 04:49 PM