Kayla W.

asked • 10/22/14

i really need your help fast

using 1 inch = 15 ft as the scale factor what are the blueprint demisions of a room in a model house that is actually 30ft x 45ft?
a bag contains 10 white golf balls and 6 striped golf balls. a glofer wants to add 112 golf ball to the bag . he wants the ratio of striped golf balls to remain the same how many of each should he add?

2 Answers By Expert Tutors


Byron S. answered • 10/22/14

5.0 (44)

Math and Science Tutor with an Engineering Background

Kayla W.

sir I really don't understand this one


Byron S.

For the first problem, if you have two fractions that are equal, you can multiply the numerator (top) of each times the denominator (bottom) of the other, and they're still equal. In the first proportion I wrote, this comes out to:
1 * 30 = x * 15
30 in*ft = (15 ft)(x in)
Divide both sides by 15 ft, and you find
2 in = x
You can do the same thing for the 45 ft dimension.


Byron S.

For the second one, the bag starts with 10 white and 6 striped balls. The easiest way to keep the ratio the same is to keep adding exactly the same number of each type of ball repeatedly. Arthur approached this by simply adding another 10 and 6 until he got to the 116 that was added.
The approach I described earlier considers the 10 and 6 balls as a group of 16 total. If you keep adding copies of these 16 balls repeatedly, you'll keep the ratio the same, and you need to do it until you get 16*7 = 116 balls added. That means you're adding 10*7=70 white balls and 6*7=42 striped balls. As you can see, both give the same result. Hopefully you understand at least one of these two methods!


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