Ratios

Advanced Math 6 · Unit 5 · ratios-grade6 · Teacher edition

ratios-grade6

Name ______________________________Date ______________

1.
A recipe uses flour and sugar in the ratio $5:2$ . If you use $35$ cups of flour, how many cups of sugar do you need?
Answer: ______________
2.
Share $84 between two people in the ratio $2:5$ . How many dollars does the person with the larger share receive?
Answer: ______________
3.
Share $84$ marbles among three children in the ratio $2:3:7$ . How many marbles does the child with the smallest share get?
Answer: ______________
4.
In a bag, the ratio of red to blue marbles is $3:4$ . There are $28$ blue marbles. How many red marbles are there?
1. (A)
  $12$
2. (B)
  $21$
3. (C)
  $36$
4. (D)
  $84$
5.
In a class the ratio of boys to girls is $2:3$ . After $4$ more boys join, the ratio becomes $4:5$ . How many students are in the class now?
1. (A)
  $45$
2. (B)
  $50$
3. (C)
  $54$
4. (D)
  $60$

Answer key — Ratios

1.
14ratios-grade6-01
$5:2 = 35:14$ (both parts $\times 7$ ). You need $\mathbf{14}$ cups of sugar.
2.
60ratios-grade6-02
$2 + 5 = 7$ parts; one part $= 84 \div 7 = 12$ . Larger share $= 5 \times 12 = \mathbf{60}$ dollars (the other gets $24; $60 + 24 = 84$ ✓).
3.
14ratios-grade6-03
$84 \div 12 = 7$ per part. Smallest share $= 2 \times 7 = \mathbf{14}$ . (Shares: $14, 21, 49$ ; sum $84$ ✓.)
4.
(B)
$21$
ratios-grade6-04
One unit $= 28 \div 4 = 7$ ; red $= 3 \times 7 = \mathbf{21}$ . ( $12$ treats $28$ as the total; $84$ multiplies instead of dividing.)
5.
(C)
$54$
ratios-grade6-05
$10k + 20 = 12k \Rightarrow k = 10$ . Originally $20$ boys and $30$ girls. Now $24$ boys and $30$ girls: $24 : 30 = 4 : 5$ ✓. Total now $= \mathbf{54}$ .