Answer: Experimental study
Step-by-step explanation:
This is an experimental study because it involves determination of the effect of each treatment on separate individuals. It involves selecting the 81 individuals randomly to be treated with a particular treatment (either of the two treatment). In experimental study the researcher apply separate treatments on a different groups and measure its effect on each of the groups.
Given a1 = 90
Common difference = adding
90 + 9 = 99, second term
99 + 9 = 108, third term
And keep doing that
You would get
90, 99, 108, 117, 126, 135
Answer:
1
Step-by-step explanation:
(6 + 3) + 21 = 6 + (3 + 21)
It's an ASSOCIATIVE PROPERTY
(a + b) + c = a + (b + c)