College

1. Simplify the following ratios to their simplest form:
- (a) [tex]160: 240[/tex]
- (b) [tex]12: 15[/tex]
- (c) [tex]\frac{1}{2}: \frac{1}{8}[/tex]
- (e) [tex]\frac{1}{2}: 1[/tex]
- (f) [tex]0.4: 0.2[/tex]
- (g) [tex]27: 0.3[/tex]
- (i) [tex]\sqrt{25}: \sqrt{625}[/tex]
- (j) [tex]\frac{4}{9}: 1.25: \frac{3}{5}[/tex]
- (k) [tex]0.006: 0.3[/tex]

2. Simplify the following rates to their simplest form:
- (a) 1000 g in 6 glasses
- (b) M800 for 3 students
- (c) 80 km in 2 hours

3. Write as a unit rate:
- (a) 828 km in 6 days
- (b) M500 earned in 12 days
- (c) 42 cars for 3 countries

4. Write in the form [tex]1: n[/tex], each of the following ratios:
- (a) [tex]2: 5[/tex]
- (b) [tex]8: 40[/tex]
- (c) [tex]5: 7[/tex]
- (d) [tex]5: 2[/tex]

5. The angles of a triangle are in the ratio [tex]3: 2: 4[/tex]. Find the size of each of the three angles.

6. Red, blue, and yellow paint are mixed in the ratio [tex]4: 7: 3[/tex] to produce [tex]308 \, \text{cm}^3[/tex] of another color. How much of each color is used?

7. Three men can build a wall in 10 hours. How many men will be needed to build the wall in 5 hours?

8. If 12 men can plow a field in 8 days, how many men can do the job in 2 days if they work at the same rate?

9. Nthabiseng is paid M376 for eight hours of work. How much would she get for five hours of work?

10. An investor paid M12000 for 500 shares of stock. Find the cost per share.

11. Two years ago, the price of a computer was M2500. Now the price is M1600 for the same computer. Find the ratio of the decrease in price to the cost price.

12. In a drink, [tex]80 \, \text{cm}^3[/tex] of pineapple juice is mixed with [tex]20 \, \text{cm}^3[/tex] of orange juice. Write the ratio of pineapple juice to orange juice and orange juice to the mixture.

13. In a class, there are 18 girls and 12 boys. Write the ratio of boys to girls.

14. Four identical minibuses carry a total of 64 passengers. How many passengers can be carried in 6 of these minibuses?

15. Divide 320 kg in the ratio [tex]1: 5: 10[/tex].

Answer :

Sure, let's tackle each question one by one for a better understanding:

### Question 1: Simplifying Ratios

(a) 160:240
To simplify, we find the greatest common divisor (GCD) of 160 and 240. The GCD is 80.
- Simplified ratio: [tex]\( \frac{160}{80}:\frac{240}{80} = 2:3 \)[/tex]

(b) 12:15
Find the GCD of 12 and 15, which is 3.
- Simplified ratio: [tex]\( \frac{12}{3}:\frac{15}{3} = 4:5 \)[/tex]

(c) [tex]\(\frac{1}{2} : \frac{1}{8}\)[/tex]
Convert to the same denominator and simplify:
- Multiply both sides by 8 to clear fractions: [tex]\( \frac{1}{2} \times 8 : \frac{1}{8} \times 8 = 4:1 \)[/tex]

(e) [tex]\(\frac{1}{2}:1\)[/tex]
This is equivalent to [tex]\(\frac{1}{2}: \frac{2}{2}\)[/tex]. Simplify by multiplying both sides by 2:
- Simplified ratio: [tex]\(1:2\)[/tex]

(f) 0.4:0.2
Divide both numbers by 0.2 (GCD of 0.4 and 0.2):
- Simplified ratio: [tex]\( \frac{0.4}{0.2}:\frac{0.2}{0.2} = 2:1 \)[/tex]

(g) 27:0.3
Convert to whole numbers by multiplying both sides by 10:
- Simplified ratio: [tex]\(270:3 = 90:1\)[/tex]

(k) 0.006:0.3
Convert to whole numbers by multiplying both sides by 1000:
- Simplified ratio: [tex]\(6:300 = 1:50\)[/tex]

### Question 2: Simplifying Rates

(a) 1000 g in 6 glasses
Divide both by their GCD (2):
- Simplified rate: [tex]\( \frac{1000}{2}:\frac{6}{2} = 500:3 \)[/tex]

(b) M800 for 3 students
Divide by common factor (which is already simplified):
- Simplified rate: [tex]\( M800:3 \)[/tex]

(c) 80 km in 2 hours
Divide by 2:
- Simplified rate: [tex]\( 40:1 \)[/tex] (km per hour)

### Question 3: Write as a Unit Rate

(a) 828 Km in 6 days
Divide 828 by 6:
- Unit rate: [tex]\( 138.0 \)[/tex] Km per day

(b) M500 earned in 12 days
Divide 500 by 12:
- Unit rate: [tex]\( \approx 41.67 \)[/tex] M per day

(c) 42 cars for 3 countries
Divide 42 by 3:
- Unit rate: [tex]\( 14.0 \)[/tex] cars per country

### Question 4: Write in the form [tex]\(1: n\)[/tex]

(a) 2:5
To express 2 as 1, divide both sides by 2:
- Form: [tex]\(1:2.5\)[/tex]

(b) 8:40
Express 8 as 1, divide both sides by 8:
- Form: [tex]\(1:5\)[/tex]

### Question 5: Triangle Angle Ratios

Angles are in the ratio 3:2:4. Let the angles be [tex]\(3x\)[/tex], [tex]\(2x\)[/tex], and [tex]\(4x\)[/tex].
- Total [tex]\(3x + 2x + 4x = 180^\circ\)[/tex]
- [tex]\(9x = 180^\circ\)[/tex]
- [tex]\(x = 20^\circ\)[/tex]

Thus, angles are [tex]\(3x = 60^\circ\)[/tex], [tex]\(2x = 40^\circ\)[/tex], [tex]\(4x = 80^\circ\)[/tex].

### Question 6: Paint Mixture

Ratio is 4:7:3 and total is [tex]\(308 \, cm^3\)[/tex].
Total parts: [tex]\(4 + 7 + 3 = 14\)[/tex].

- Red: [tex]\( \frac{4}{14} \times 308 = 88.0 \, cm^3 \)[/tex]
- Blue: [tex]\( \frac{7}{14} \times 308 = 154.0 \, cm^3 \)[/tex]
- Yellow: [tex]\( \frac{3}{14} \times 308 = 66.0 \, cm^3 \)[/tex]

### Question 7: Building a Wall

3 men can build a wall in 10 hours. How many men for 5 hours?
Using the relation [tex]\[ \text{men} \times \text{hours} = \text{constant} \][/tex]
- [tex]\(3 \times 10 = x \times 5 \)[/tex]
- [tex]\(x = \frac{30}{5} = 6\)[/tex] men

### Question 8: Ploughing a Field

12 men can plough in 8 days. For 2 days:
- [tex]\(12 \times 8 = x \times 2\)[/tex]
- [tex]\(x = \frac{96}{2} = 48\)[/tex] men

### Question 9: Payment for Work Hours

Payment M376 for 8 hours. Find for 5 hours:
- [tex]\(\frac{M376}{8} \times 5 = M235.0\)[/tex]

### Question 10: Cost per Share

M12000 for 500 shares:
- [tex]\(\frac{M12000}{500} = M24.0\)[/tex] per share

### Question 11: Price Decrease Ratio

Old: M2500, New: M1600. Decrease is M900:
- Ratio of decrease to old price: [tex]\(900:2500\)[/tex]

### Question 12: Juice Ratios

Pineapple [tex]\(80 \, cm^3\)[/tex], Orange [tex]\(20 \, cm^3\)[/tex]:
- Pineapple to Orange: [tex]\(80:20\)[/tex]
- Orange to Total Mix: [tex]\(20:(80 + 20) = 20:100\)[/tex]

### Question 13: Ratio of Boys to Girls

12 boys and 18 girls:
- Ratio: [tex]\(12:18\)[/tex] which simplifies to [tex]\(2:3\)[/tex]

### Question 14: Passengers in Minibuses

64 passengers in 4 minibuses. Find how many in 6:
- Passengers per bus: [tex]\( \frac{64}{4} = 16\)[/tex]
- In 6 buses: [tex]\(16 \times 6 = 96\)[/tex]

### Question 15: Divide Weight in Ratio [tex]\(1:5:10\)[/tex]

Total weight: 320 kg.
- Total parts: [tex]\(1 + 5 + 10 = 16\)[/tex]

- First part: [tex]\( \frac{1}{16} \times 320 = 20 \, kg \)[/tex]
- Second part: [tex]\( \frac{5}{16} \times 320 = 100 \, kg \)[/tex]
- Third part: [tex]\( \frac{10}{16} \times 320 = 200 \, kg \)[/tex]

I hope this helps clarify each part of the question!