math. please help.

Question

1. An architect built a scale model of a shopping mall. On the model, a circular fountain is 15 inches tall and 7.5 inches in diameter. If the actual fountain is to be 10 feet tall, what is its diameter?

2. Hidemi is a waiter. He waits on a table of 4 whose bill comes to $90.27. If Hidemi receives a 15% tip, approximately how much will he receive?

3. Salar's Drama class is performing a play. He wants to buy as many tickets as he can afford. If tickets cost $3.50 each and he has $15.25 to spend, how many tickets can he buy?

4. A man that is 6 feet tall casts a shadow 5 feet long. At the same time, a lamppost beside the man casts a shadow 25 feet long. How tall is the lamppost?


5. The fuel for a chain saw is a mix of oil and gasoline. The ratio of ounces of oil to gallons of gasoline is 4:12. There are 24 gallons of gasoline. How many ounces of oil are there?

Answer 1

Here is the answer to #1:    This is a proportional math problem.

 

The model has a top=7.5 inches.   model height=15 inches

 

The real object's top=X                  real object's height=10 feet

 

 

There is more than one way to set up the problem.

 

model height/ real real object's height         =     model top/ real object's top

 

 

15/10  =  7.5/ X          Now, cross multiply:     15*X= 10*7.5                 15X=75         

 

Divide both sides by "15," and you're done.  You'll have the diameter of the real object in feet.