Does this represent a direct proportion? If so what is the equation?
10y=50x
Yes,
y=5x
3/7= x/21
x=9
If a factory makes 40 cookies in 4 hours, what is the constant of proportionality (unit rate)?
10 cookies per hour
1.5/5 = x/ 25
x=7.5
Does this represent a direct proportion? If so, what is the equation? If not why?
No, it does not pass through the origin.
5/x=10/25
x=12.5
An artist does 12 sketches in 3 hours. How many sketches in 10 hours?
40 sketches
A table shows the relationship between x and y. When x=2, y=10. When x=4, y=20. If this is a direct proportion, what is the value of y when x=0?
y=0
Does this represent a direct proportion? Explain.

Yes, because it is a straight line and passes through the origin.
0.4/x=2/20
x=4
A student types 105 words in 3 minutes. Write the direct proportion equation where y represents the number of words and x represents the number of minutes.
y=35x
A train travels 150 miles in 150 minutes. How many minutes would it take the train to travel 20 miles?
20 minutes
Does this represent a direct proportion? If so, what is the equation? If not, explain why.
No, all ratios are not equal.
Ming was planning a trip to Western Samoa. Before going, she did some research and learned that the exchange rate is 6 Tala for $2. How many Tala would she get if she exchanged $6?
18 Tala
A chef can roll 15 sushi rolls in 20 minutes. How many hours would it take the chef to make 90 rolls?
120 minutes or 2 hours.
A student reads 15 pages in 20 minutes. Write a direct proportion equation to represent this, where y is pages and x is minutes.
y=0.75x
Does this represent a direct proportion? If so, what is the equation? If not, explain why
.
Yes,
y=13x
The currency in Argentina is the Peso. The exchange rate is approximately $3 = 1 Peso. At this rate, how many Pesos would you get if you exchanged $121.10?
40.37 Pesos
A hot air balloon travels at a constant speed. The distance it travels is a direct proportion to the time it spends in the air. In 45 minutes, the balloon travels 9 miles. If the balloon travels for 210 minutes, how many miles will it go?
42 miles
A direct proportion graph passes through the point (4, 30). What is the constant of proportionality (k), and what would the y value be when x=10
k = 7.5
and
y = 75