Answer:

Step-by-step explanation:
Sum the frequency column to find the total number of students
total = 2 + 9 + 5 + 5 + 3 = 24
number of students finished in less than 20 mins = 2 + 9 + 5 = 16
fraction of students =
= 
Answer:
-18x-24
Step-by-step explanation:
15-9(-3x-4)
6(-3x-4)
-18x-4
-18x-24
Answer:
6 plates needed
Step-by-step explanation:
2 dozen= 24
3 dozen = 36
24+36=60
60 ÷ 10=6
6 plates needed
Step-by-step explanation:
the question is z²=1
taking square root on both sides
√z² = √1
the square root and the square cancel out each other
it gives
z=±1
that means either z=+1 or z=-1
so the solutions are 1 and -1
I do suppose that you refer to adding these quantities:
6/1 + 21 = 6 + 21 = 27
<span>and
6/10 + 21
</span>= 3/5 + 21
= 3/5 + 105/5
<span>= 108/5</span>