| Problem |
Solution |
|
1) Mrs. Roscoe noticed at the dance that for every three boys that walked in the door there were
five girls with them. When she counted the tickets she found that the total number of boys and
girls at the dance was 248. How many girls attended the dance? |
Method 1: Use fractions:
1. Out of every 8 students 5 were girls.
2. The fraction that were girls is 5/8.
3. That fraction of the total is
5/8 x 248 = 155 girls.
|
Method 2: guess-and-check.
| # boys | #girls | Total |
| 120 | 200 | 320 |
| 93 | 155 | 248 |
|
|
2) William needed to change the oil in his truck. His truck holds 12 and 3/4 quarts of oil. Behind
the seat he finds 2 and 3/5 quarts of oil. On the shelf in his garage he finds 3 and 2/3 quarts.
How many additional quarts will he need to purchase? |
You need to add and subtract fractions with different denominators:
1. Add the amount of oil that William already has: =
2 3/5 + 3 2/3 = 13/5 + 11/3 = 39/15 + 55/3 =
94/15 = 6 4/15 quarts
2. Subtract that from the amount his truck holds =
12 3/4 - 6 4/15 = 51/4 - 94/15 = 765/60 - 376/60 =
389/60 = 6 16/60 = 6 4/15 quarts.
3. Round this up to the next whole quart = 7 quarts
|
|
3) Tyree and Huang Fu are studying a set of new words for Spanish class. They both decide to
make study cards. Tyree writes 7 words on each card except the last card has 6 words. Huang
Fu writes 9 words on each card except the last card has 7 on it. What is the smallest number of
words there could be in the whole set? |
Fill in the following table: (M is the total number of words)
| N | M =
7 x N + 6 | Remainder of
M/9 |
| 1 | 13 | 4 |
| 2 | 20 | 2 |
| 3 | 27 | 0 |
| 4 | 34 | 7 |
|
