If there are 70 chairs but only 20 rows then that means he will have to set up 3.5 chairs per row, or Brook could set up 14 rows with 5 chairs in each row.
Srry if that didn't help but that's what i got from that.
Answer:
The correct answer is option 3. (20, 4, 5)
Step-by-step explanation:
To solve this problem we use the substitution method.
(i)
(ii)
(iii)
We start by clearing x in (iii) and clearing y in (ii).
(iii)
(ii)
Now we substitute (iii) in (ii)
(iv)
Now we substitute (iii) and (iv) into (i) and clear z.
(v)



If
(v)
We substitute (v) in (iii) and then substitute (v) in (iv)

The correct answer is option 3.
100b + 70 because it can't be simplified further than that