Looking for trustworthy answers? Westonci.ca is the ultimate Q&A platform where experts share their knowledge on various topics. Ask your questions and receive detailed answers from professionals with extensive experience in various fields. Explore comprehensive solutions to your questions from a wide range of professionals on our user-friendly platform.

Ratio and Proportion

8. a) If [tex]p: q=1: 2[/tex] and [tex]q: r=4: 3[/tex], find [tex]\( r \)[/tex].

b) If [tex]a: b=2: 3[/tex] and [tex]b: c=6: 5[/tex], find [tex]\( c \)[/tex].

9. Find the value of [tex]\( x \)[/tex] in the following proportions:

a) [tex]x: 3=4: 6[/tex]

b) [tex]2: x=6: 9[/tex]

c) [tex]5: 4=x: 12[/tex]

10. a) Two numbers are in the ratio of [tex]2: 5[/tex]. If the sum of these two numbers is 70, find the numbers.

b) The ratio of the length and breadth of a rectangular ground is [tex]4: 3[/tex] and the breadth is 75 m. Find the length of the ground.


Sagot :

Sure, let's tackle these ratio and proportion problems step-by-step:

### Question 8

#### Part a)
Given:
1. [tex]\( p: q = 1: 2 \)[/tex]
2. [tex]\( q: r = 4: 3 \)[/tex]

We need to find [tex]\( r \)[/tex].

First, express both ratios with the same [tex]\( q \)[/tex].
1. From [tex]\( p: q = 1: 2 \)[/tex], we have:
[tex]\[ p = 1 \text{ unit}, \quad q = 2 \text{ units} \][/tex]

2. From [tex]\( q: r = 4: 3 \)[/tex], we have:
[tex]\[ q = 4 \text{ units}, \quad r = 3 \text{ units} \][/tex]

To combine these ratios, find a common value for [tex]\( q \)[/tex]. The least common multiple (LCM) of 2 and 4 is 4.

Scale the first ratio [tex]\( p: q \)[/tex]:

[tex]\[ p = 1 \text{ unit} \quad \text{scaled by factor of 2:} \quad p = 2 \text{ units} \][/tex]
[tex]\[ q = 2 \text{ units} \quad \text{scaled by factor of 2:} \quad q = 4 \text{ units} \][/tex]

So, [tex]\( p: q: r = 2: 4: 3 \)[/tex].
Thus, [tex]\( r \)[/tex] in terms of [tex]\( p \)[/tex] is [tex]\( r = 3 \)[/tex].

### Part b)
Given:
1. [tex]\( a: b = 2: 3 \)[/tex]
2. [tex]\( b: c = 6: 5 \)[/tex]

We need to find [tex]\( c \)[/tex].

First, express both ratios with the same [tex]\( b \)[/tex].
1. From [tex]\( a: b = 2: 3 \)[/tex], we have:
[tex]\[ a = 2 \text{ units}, \quad b = 3 \text{ units} \][/tex]

2. From [tex]\( b: c = 6: 5 \)[/tex], we have:
[tex]\[ b = 6 \text{ units}, \quad c = 5 \text{ units} \][/tex]

To combine these ratios, find a common value for [tex]\( b \)[/tex]. The least common multiple (LCM) of 3 and 6 is 6.

Scale the first ratio [tex]\( a: b \)[/tex]:

[tex]\[ a = 2 \text{ units} \quad \text{scaled by factor of 2:} \quad a = 4 \text{ units} \][/tex]
[tex]\[ b = 3 \text{ units} \quad \text{scaled by factor of 2:} \quad b = 6 \text{ units} \][/tex]

So, [tex]\( a: b: c = 4: 6: 5 \)[/tex].
Thus, [tex]\( c \)[/tex] in terms of [tex]\( a \)[/tex] is [tex]\( c = 5 \)[/tex].

### Question 9

#### Part a)
Given the proportion:
[tex]\[ x: 3 = 4: 6 \][/tex]

Cross-multiply to solve for [tex]\( x \)[/tex]:
[tex]\[ x \cdot 6 = 4 \cdot 3 \][/tex]
[tex]\[ 6x = 12 \][/tex]
[tex]\[ x = 2 \][/tex]

#### Part b)
Given the proportion:
[tex]\[ 2: x = 6: 9 \][/tex]

Cross-multiply to solve for [tex]\( x \)[/tex]:
[tex]\[ 2 \cdot 9 = 6 \cdot x \][/tex]
[tex]\[ 18 = 6x \][/tex]
[tex]\[ x = 3 \][/tex]

#### Part c)
Given the proportion:
[tex]\[ 5: 4 = x: 12 \][/tex]

Cross-multiply to solve for [tex]\( x \)[/tex]:
[tex]\[ 5 \cdot 12 = 4 \cdot x \][/tex]
[tex]\[ 60 = 4x \][/tex]
[tex]\[ x = 15 \][/tex]

### Question 10

#### Part a)
The problem statement is incomplete, so it's not possible to provide a solution.

#### Part b)
Given:
- The ratio of length to breadth is [tex]\( 4: 3 \)[/tex].
- The breadth is [tex]\( 75 \)[/tex] meters.

We need to find the length.

From the ratio:
[tex]\[ \frac{\text{length}}{\text{breadth}} = \frac{4}{3} \][/tex]

Given the breadth:
[tex]\[ \text{length} = \frac{4}{3} \times 75 \][/tex]
[tex]\[ \text{length} = 100 \][/tex]

Thus, the length of the ground is [tex]\( 100 \)[/tex] meters.