Answer:
correct option is C) 2.8
Step-by-step explanation:
given data
string vibrates form = 8 loops
in water loop formed = 10 loops
solution
we consider mass of stone = m
string length = l
frequency of tuning = f
volume = v
density of stone =
case (1)
when 8 loop form with 2 adjacent node is
so here
..............1

and we know velocity is express as
velocity = frequency × wavelength .....................2
= f ×
here tension = mg
so
= f ×
..........................3
and
case (2)
when 8 loop form with 2 adjacent node is
..............4

when block is immersed
equilibrium eq will be
Tenion + force of buoyancy = mg
T + v ×
× g = mg
and
T = v ×
- v ×
× g
from equation 2
f ×
= f ×
.......................5
now we divide eq 5 by the eq 3

solve irt we get

so
relative density 
relative density = 2.78 ≈ 2.8
so correct option is C) 2.8
The total cost would be $5.98
hope this helps! :)
Answer:
1a) Length = 7x + 3 & Width = 4x - 2
1b) Area = 
1c) Area = 2774 sq. m
2. 
Step-by-step explanation:
1a)
The length given as words is "3 more than 7 times x"
The width given as words is "4 times x minus 2"
The expression for length would be 7x + 3
The expression for width would be 4x - 2
1b)
The area is length * width
Since we already know the algebraic expressions for length and width from part (a) above, we use the formula:
Area = (7x+3)(4x-2) = 28x^2 -14x + 12x - 6 = 28x^2 -2x -6
Area = 
1c)
Given x = 10, we put this into the area expression we found in (b) above.Let's see:

Area = 2774 sq. m
2.
We can group the first two terms and next two terms and write up:

That's the factored form.