Ratios Day 4
Presentation Problems
1. When Tim had 48 comic books, the ratio of his comic books to Toby’s comic books
was 4:5. Tim bought two more comic books. What is the new ratio of his comic books
to Toby’s?
48
New Ratio
?:?
50 : 60
5:6
After
Tim’s comic books
12
12
12
12
Toby’s comic books
12
12
12
12
2
= 50
12
= 60
4 units = 48
48 ÷ 4 = 12
1 unit = 12
48 + 2 = 50
5 units of 12
The new ratio of Tim’s comic books to Toby’s is 5:6.
5 • 12 = 60
Milk It! How many comic books do they have altogether?
2. The French Club had 76 members, with the ratio of boys to girls at 9:10. When four
more boys joined the club, what was the new ratio of boys to girls?
36
After
Boys
4
4
4
4
4
4
4
4
4
4
= 40
Girls
4
4
4
4
4
4
4
4
4
4
= 40
= 76
9 units = 76
76 ÷ 19 = 4
9 units of 4
9 • 4 = 36
36 + 4 = 40
10 units of 4
10 • 4 = 40
New Ratio
?:?
40 : 40
1:1
The new ratio of boys to girls is 1:1.
Milk It! What percent of the club were boys before? After?
3. The ratio of Tonya’s CDs to Anita’s CDs was 2:3. Anita had 42 CDs. When Tonya
lost four CDs, what was the new ratio of Tonya’s CDs to Anita’s?
14
Tonya’s CDs
14
s
Anita’s CDs
14
4
14
= 24
14
= 42
New Ratio
?:?
24 : 42
4:7
3 units = 42
42 ÷ 3 = 14
1 unit = 14
2 units of 14
2 • 14 = 28
The new ratio of Tonya’s CDS to Anita’s CDs is 4:7.
Milk It! How many CDs do they have altogether?
28 - 4 = 24
Ratios Day 4
Assessment Problems
1. A jar contained 100 marbles, all green and yellow. The ratio of green marbles to
yellow marbles was 2:3. When 8 more green marbles are added, what is the new ratio
of green marbles to yellow marbles?
40
Green Marbles
20
After
20
8
= 48
= 100
s
Yellow Marbles
20
20
5 units = 100
100 ÷ 5 = 20
1 unit = 20
20
= 60
2 units of 20
3 units of 20
2 • 20 = 40
3 • 20 = 60
New Ratio
?:?
48 : 60
4:5
40 + 8 = 48
+
The new ratio of green to yellow marbles is 4:5.
2. A swimming pool had 70 people in it, with the ratio of males to females at 5:9. If 8
more males get into the pool, what is the new ratio of males to females?
25
After
Males
s
Females
5
5
5
5
5
8
= 33
= 70
5
5
5
14 units = 70
70 ÷ 14 = 5
1 unit = 5
5
5
5
5
5
5
5 units of 5
9 units of 5
5 • 5 = 25
9 • 5 = 45
The new ratio of males to females is 11:15.
= 45
25 + 8 = 33
+
New Ratio
?:?
33:45
11:15