The order in which a ratio is written is
1. In the lunchroom, there were 100 milk cartons at lunch. When lunch was over, 80 cartons of
milk had been purchased.
What is the ratio of the number of milk cartons purchased to the total number of milk
cartons?

The answer is in the image 

SI=(P*R*T)/100

P=2000

R=1.5

T=6

SI=(2000*1.5*6)/100

=(2000*9)/100

=180

Neil will earn interest of 180

Cost of 7 gallons=$24.50

Cost of 1 gallon=24.50/7=3.5

Cost of 15 gallons=15*3.5=52.5

Cost of 15 gallons will be $52.5

y=2x+15

where y=Value of coin

x=Age in years

Value of coin after 19 years=2*19+15

=$53

Therefore, Value after 19 years=$53

The wood before starting =12 feet

Left wood=6 feet

Wood used till now=12-6=6 feet

Picture frame built till now= 6/(3/4)

=8 pieces

Therefore, till now 8 pieces have been made.

The answer is in the image 

Volume of rectangular prism=length * width * height

Given,

length=3/8cm

breadth=5/8cm

height=7/8cm

therefore volume=(3/8)*(5/8)*(7/8)

                           =105/512 cm3

Speed = distance/time

distance = 60 feet

time = 30 sec

speed = 60/30

          =  2 feet/sec

Given,

Area of base = 6ft

Volume = 15ft

We know,

Volume = area of base * height

15 = 6 * height   

height = 15/6

   = 2.5ft   

Given eq k = 10t-19

Given t = -7

k = 10*(-7) - 19

  = -70 -19

   =-89