I’m pretty sure it’s c , sorry if it’s wrong tho
Answer:
9 bags
Step-by-step explanation:
First we will need to calculate the area of their entire backyard, which has a shape of trapezium.
So the formula for the area of a trapezium is 
a and b are the lenghts of the parallel sides and h is the height.
From the picture 
Then we plug into our formula
square feet
To get the number of bags required we just simply divide the aree of their entire yard by the space that 1 bag covers. We get:
bags
This is more than 8 bags so they will need 9 bags to cover their entire yard.
Answer:
4 boys, 3 girls
Step-by-step explanation:
brothers of John ⇒ x
sisters of John ⇒ y
John has as many brothers as sisters:
- x = y
brothers of Emily ⇒ x + 1 (Emily have the same amount of brother as John, plus one (John))
sisters of Emily ⇒ y -1 (Emily have the same amount of sister as John, minus one (herself))
Emily has twice as many brothers as sisters:
- 2 (y-1) = x+ 1
Now we have a system of 2 equations and 2 variables
x=y (I)
2y - 2 = x + 1 (II)
____________
Replace x in equation II
2y - 2 = y + 1
2y - y = 2 + 1
y = 3
____________
Replace y in equation I
x = y = 3
That mean that John have 3 brothers plus himself, there is 4 boys in the family and John have 3 sister, so there is 3 girls in the family