Answer:

Step-by-step explanation:
The initial number of mosquitoes is 400000, and they double each day. This represents an exponential growth equation. If t represent days and P represent the population of the mosquitoes, hence this can be represented by the equation:

Also, the predators eat the mosquitoes at a rate of 40,000 mosquitoes/day. This means that each day, the mosquitoes reduce by 40000t, therefore this can be represented by:

Yes correct x is 48.02 here is why.
simplify 45.6/109.2 to 0.417582
multiply both sides by 115
simplify 0.417582 x 115 to 48.021978
switch sides
Answer: x = 48.021978
#5) 7.065 sq. ft.
#6) 36 ft
#7) 200.96 sq. ft.
#8) 176.625 sq. ft.
Explanation
#5) Converting 18 inches to feet, 18/12 = 1.5. The area of the circle would be given by A=3.14(1.5)² = 3.14(2.25) = 7.065 sq. ft.
#6) The radius is 18 inches, so the diameter is twice that: 18*2 = 36 inches. Converting this to feet, we have 36/12 = 3 feet. Each stone is 3 feet across. Laying 12 of them against each other would give us a total length of 12*3 = 36 feet.
#7) The radius of the entire mirror with frame is 20/2 = 10. The area of the entire mirror with frame is A=3.14(10²) = 3.14(100) = 314 in².
The area of the mirror without the frame is A=3.14(6²) = 3.14(36) = 113.04 in².
The difference between the two will give the area of the frame:
314-113.04 = 200.96 in²
#8) The area of the circular region is given by A=3.14(7.5²) = 176.625 ft²