Answer:

Step-by-step explanation:
I have attached the explanation above. hopefully this will help
Answer:
There were 39 children at the party
Step-by-step explanation:
Here, we want to know the number of children at the party
To do this, we have to add the y-values ( frequencies of the age grades)
We have this as;
8 + 8 + 7 +10 + 6 = 39
-2/3x + 2.8 = -8.2 what is x
Add 2.8 on both side of the equation
-2/3x=-11
Divide both side by -2/3
x=33/2
Check: -2/3(33/2)+ 2.8 = -8.2
-11+2.8=-8.2
-8.2=-8.2
Answer is x=33/2
Answer:
First term (a) =8
Common difference (d)= t2-t1
=12-8
=4
Now, sum of first 31th term (tn31) =n/2{2a+(n-1)d}
= 31/2{2×8+(31-1)4}
=31/2{16+(30×4)
=31/2(16+120)
=31/2×126
=31×63
Step-by-step explanation:
Similarly use 19 as (n) for the 19th term