#7 and #8
Solve these with proportions. Set them up like this:
Say I have a question that said "Arjun had Rs. 10, and his friend Raghav borrowed Rs. 5, what percentage of Arjun's amount did Raghav borrow?". 10 is the whole. It is the total amount of money that they have. 5 is the part. You are looking for the percentage. The 100 will always stay the same. Put the values that you know into the proportions, and replace what you don't know with the variable x. Like so:
To solve this, use cross multiplication. Multiply the top left with the bottom right, and the bottom left with the top right. You will get:
5(100) = 10x
Simplify.
500 = 10x
Now, to solve this, you must isolate the x. To do this, divide both sides by 10, to get:
50 = x.
50 is your percentage.
You can solve this kind of problem by just remembering the proportion, filling in what you know, and then solving!
#8 and #9
To solve these types of problems, set up an equation.
Say that I had the question "Sowmya is baking cupcakes. She has 10 cups of flour, and she uses 2 cups for each cupcake. How many cupcakes can she bake?
What do you know?
You know she has 10 cups in total. You know that she uses 2 cups per cupcake.
So, you will set up the equation like this:
2x = 10
Where x is the number of cupcakes she makes.
To solve, you will isolate the variable by dividing both sides by 2 to get:
x = 5.
Sowmya can bake 5 cupcakes with 10 cups of flour.
Hope this helps!