Given :
On average, a refrigerator door is opened 99 times each day.
Len has two refrigerators in his house.
To Find :
How many times in a 8−week period are the refrigerator doors opened.
Solution :
Number of times door opened for 2 refrigerator , n = 99×2 = 198.
Number of days in 8 week , d = 8×7 = 56 days.
So, total number of times doors open in a period of 8-week is :

Therefore, refrigerator doors are opened about 11088 times.
Hence, this is the required solution.
If the triangles ABC and A'B'C' are similar, then
angle A = angle A'
8x-10 = 6x+10
8x-6x = 10+10
2x = 20
x = 20/2
x = 10
So angle A is
angle A = 8x-10
angle A = 8*10-10
angle A = 80-10
angle A = 70
making that the measure of angle A' as well
This is why the answer is choice A
Using the Pythagorean Theorem a^2 + b^2 = C^2
a and b are the sides and C is the Hypotenuse.
The picture you have sides of a and 15 and the hypotenuse is 17
The formula becomes a^2 + 15^2 = 17^2
This diagram show the sound wave have a high pitch