Is that the Algebra work/practice book? If so, go into algebra nation and they have videos where they go step by step through the questions. Hope this helps?
Answer:
a)
b) 
c) 
Step-by-step explanation:
Part a
The significance level given is
and the degrees of freedom are given by:

Since we are conducting a right tailed test we need to find a critical value on the t distirbution who accumulates 0.1 of the area in the right and we got:

Part b
The significance level given is
and the degrees of freedom are given by:

Since we are conducting a left tailed test we need to find a critical value on the t distirbution who accumulates 0.01 of the area in the left and we got:

Part c
The significance level given is
and
and the degrees of freedom are given by:

Since we are conducting a two tailed test we need to find a critical value on the t distirbution who accumulates 0.025 of the area on each tail and we got:

Selection D is the equivalent form of the given expression.
_____
The nominal annual interest rate in this problem is 40%. If it were compounded half-yearly, the formula would be x(1.2)^(2t) or x(1.44)^t. Apparently, this problem is more concerned with the equivalent form of the expression than it is with half-yearly compounding.
It’s 7 in that’s the only answer that makes sense
Answer:
59 ° F
Step-by-step explanation:
F = 9/5 C + 32
= 9/5 (15) + 32 = 59 ° F