26,152 views
12 votes
12 votes
For an area of 18m²,the amount of a fertilizer required is 675g.

a) how much is needed to fertilise 11m²?
b) what area will 862.5g fertilise?

User Chihiro
by
2.9k points

2 Answers

18 votes
18 votes

Answer:

Explanation:

This is a rate problem so using ratios is a good way to calculate the answer for different areas or amounts

675 g per 18 m² 675/18 g/m²

a) How many grams for 11m²

675/18 g/m² = ??? / 11 m² i cross multiply 675 times 11 divide by 18

or more simply multiply both side by 11

solving for the ???

(675)(11) g m² / 18 m² = ??? g = 412.5 grams ( the m²/m² cancel)

b) what area can be fertilised with 862.5 g? again applying ratio

this time we know the g and want to calculate an unknown area

675 / 18 = 862.5 / ??? this will take one more step since the ??? is

in the denominator

18 / 675 = ??? / 862.5 I just inverted both sides

18m² / 675g = ??? / 862.5g again simply multiply both sides by 862.5g

(18m²)(862.5g) / (675g) = ??? this time the grams cancel leaving m²

??? = 23 m²

User Neri
by
3.0k points
10 votes
10 votes

Answer:

a) 412.5g

b)23m²

Explanation:

a)18m²=675g

11m²=x

by cross multiplication,

18x=11×675

18x=7425

x=7425/18

x=412.5g

b)18m²=675g

y=862.5g

18×862.5=675y

15525=675y

15525/675=y

y=23m²

User Huy Tower
by
2.9k points