First, the formula for the average of a data set must be defined. It is calculated by adding all the numbers in the data set and then dividing the sum by the number of data. In this case, the average is set to be equal to $400 with the total number of data being 3, with the September expenditure set as an unknown, x. The equation is then set-up to be: 400 = (401.5 + 250 + x)/3. Thus, Joshua can spend as much as $ 548.5 to be able to have the same average as in his second quarter expenditure.
Answer:

Step-by-step explanation:
Given

Required
Find a
Take log of both sides

Apply law of logarithm

Divide both sides by a

Multiply both sides by -9

Apply law of logarithm

Cancel out log

Rewrite as:

Apply law of indices


Answer:
m∠B =
.
Step-by-step explanation:
Since the three sides of the triangle are given, then we apply cosine rule.
=
+
- 2ac Cos B
But, a = 660 cm, b = 680 cm, and c = 100 cm.
So that;
=
+
-2(660 x 100) Cos B
462400 = 435600 + 10000 - 132000 Cos B
462400 = 445600 - 132000 Cos B
132000 Cos B = 445600 - 462400
= -16800
Cos B = 
= -0.1273
B =
-0.1273
= 
Thus, measure of ∠B is
.