Find the difference between the average number of beaches in D, E and C and the average number of mountains in B, A and E.

Read the following bar graph and table carefully and answer the questions given below. The bar graph shows total number of beaches in five different countries. The table shows percentage of mountains out of total beaches and mountains together in these countries.

Countries	Percentage of mountains out of total beaches and mountains together
A	60%
B	75%
C	20%
D	80%
E	50%

To find the difference between the average number of beaches in countries D, E, and C and the average number of mountains in B, A, and E, we need to extract the values from the bar graph and the table.

Step 1: Find the number of beaches in each country from the bar graph
By analyzing the bar graph, the number of beaches in each country is:
- Country A: 100
- Country B: 80
- Country C: 120
- Country D: 150
- Country E: 60

Step 2: Calculate the number of mountains for each country
The table gives the percentage of mountains out of the total beaches and mountains combined.
Let $B$ be the number of beaches, $M$ be the number of mountains, and $P$ be the percentage of mountains.
The relationship is given by:
$\frac{M}{B+M}=\frac{P}{100}$
Rearranging the formula to solve for the number of mountains ($M$):
$M=\frac{B\times P}{100-P}$

Now we calculate the number of mountains for countries A, B, and E:
- Country A: $B=100$, $P=60\%$
$M_A=\frac{100\times 60}{100-60}=\frac{6000}{40}=150$
- Country B: $B=80$, $P=75\%$
$M_B=\frac{80\times 75}{100-75}=\frac{6000}{25}=240$
- Country E: $B=60$, $P=50\%$
$M_E=\frac{60\times 50}{100-50}=\frac{3000}{50}=60$

Step 3: Find the average number of beaches in D, E, and C
The number of beaches in D, E, and C are 150, 60, and 120 respectively.
$\text{Average beaches}=\frac{150+60+120}{3}=\frac{330}{3}=110$

Step 4: Find the average number of mountains in B, A, and E
The number of mountains in B, A, and E are 240, 150, and 60 respectively.
$\text{Average mountains}=\frac{240+150+60}{3}=\frac{450}{3}=150$

Step 5: Calculate the difference between the averages
$\text{Difference}=150-110=40$

Thus, the difference between the averages is 40.