Find the difference per row:
10 seats in the first row
30 seats in the sixth row:
30 -10 = 20 seats difference.
6-1 = 5 rows difference.
20 seats / 5 rows = 4 seats per row.
This means for every additional row, there are 4 more seats per row.
The equation would be:
Sn = S +(n-1)*d
Where d is the difference = 4
S = number of seats from starting row = 10
n = the number of rows wanted
S(11) = 10 + (11-1)*4
S(11) = 10 + 10*4
S(11) = 10 + 40
S(11) = 50
Check:
Row 6 = 30 seats
Row 7 = 30 + 4 = 34 seats
Row 8 = 34 + 4 = 38 seats
Row 9 = 38 + 4 = 42 seats
Row 10 = 42 + 4 = 46 seats
Row 11 = 46 + 4 = 50 seats.
answer
width = 98 cm
length = 105 cm
set up equations
the perimeter of a rectangle = 2W + 2L
p = 2W + 2L
the perimeter is also 406
406 = 2W + 2L
we know that the length of the rectangle is 7 cm longer than the width so
L = W + 7
substitute equations and solve for width
plug L into p = 2W + 2L to get
406 = 2W + 2(W + 7) distribute the 2 to the terms in the parentheses
406 = 2W + 2W + 14
406 = 4W + 14
392 = 4W
W = 98
substitute equations and solve for length
now that we know the width, we can substitute W in L = W + 7 to find length
L = W + 7
L = 98 + 7
L = 105
final dimensions
width = 98 cm
length = 105 cm
Dispenser C is your answer
16/25 x 4/4 = 64/100
64/100 = 0.64, or 64%
Your answer is Dispenser C
hope this helps
Answer: On the 29th day
Step-by-step explanation:
According to this problem, no lilypad dies and the lilypads always reproduce, so we can apply the following reasoning.
On the first day there is only 1 lilypad in the pond. On the second day, the lilypad from the first reproduces, so there are 2 lilypads. On day 3, the 2 lilypads from the second day reproduce, so there are 2×2=4 lilypads. Similarly, on day 4 there are 8 lilypads. Following this pattern, on day 30 there are 2×N lilypads, where N is the number of lilypads on day 29.
The pond is full on the 30th day, when there are 2×N lilypads, so it is half-full when it has N lilypads, that is, on the 29th day. Actually, there are 
lilypads on the 30th, and 
lilypads on the 29th. This can be deduced multiplying succesively by 2.
