Question

Difficulty: HardRatios, Rates, and Proportions

A textile mill uses two weaving looms, Loom PP and Loom QQ, to produce a fabric blend composed of silk, wool, and cotton.

- Loom PP produces silk, wool, and cotton in the ratio 2:3:52 : 3 : 5 by weight, operating at a constant output rate of 120 kg per hour120\text{ kg per hour}.
- Loom QQ produces silk, wool, and cotton in the ratio 1:4:31 : 4 : 3 by weight, operating at a constant output rate of 160 kg per hour160\text{ kg per hour}.

If both looms operate simultaneously for 5 hours, what is the ratio of the total weight of wool produced to the total weight of cotton produced in the combined output?

  1. 29:3029 : 30Answer
  2. B
    7:87 : 8
  3. C
    32:3532 : 35
  4. D
    29:7029 : 70
  5. E
    30:2930 : 29

Answer

The ratio of the total weight of wool produced to the total weight of cotton produced is 29:3029 : 30.
To find the overall ratio of wool to cotton, determine the actual mass of each material produced per hour by each machine. Loom PP outputs 310×120=36 kg\frac{3}{10} \times 120 = 36\text{ kg} of wool and 510×120=60 kg\frac{5}{10} \times 120 = 60\text{ kg} of cotton per hour. Loom QQ outputs 48×160=80 kg\frac{4}{8} \times 160 = 80\text{ kg} of wool and 38×160=60 kg\frac{3}{8} \times 160 = 60\text{ kg} of cotton per hour. Combining both looms yields 116 kg116\text{ kg} of wool and 120 kg120\text{ kg} of cotton per hour. Over 5 hours, the combined output is 580 kg580\text{ kg} of wool and 600 kg600\text{ kg} of cotton. The ratio of total wool to total cotton is 580:600580 : 600, which simplifies to 29:3029 : 30.

Step-by-Step Solution

1
Calculate the hourly production rates of wool and cotton for Loom PP.
Loom PP produces fabric at 120 kg/hr120\text{ kg/hr} with ratio parts 2+3+5=102 + 3 + 5 = 10.
- Wool rate from P=310×120=36 kg/hrP = \frac{3}{10} \times 120 = 36\text{ kg/hr}
- Cotton rate from P=510×120=60 kg/hrP = \frac{5}{10} \times 120 = 60\text{ kg/hr}
Converting the ratio into component rates by multiplying each component's fraction by Loom PP's total hourly output.
2
Calculate the hourly production rates of wool and cotton for Loom QQ.
Loom QQ produces fabric at 160 kg/hr160\text{ kg/hr} with ratio parts 1+4+3=81 + 4 + 3 = 8.
- Wool rate from Q=48×160=80 kg/hrQ = \frac{4}{8} \times 160 = 80\text{ kg/hr}
- Cotton rate from Q=38×160=60 kg/hrQ = \frac{3}{8} \times 160 = 60\text{ kg/hr}
Converting the ratio into component rates by multiplying each component's fraction by Loom QQ's total hourly output.
3
Determine total quantities produced over the 5-hour period.
Total wool =(36+80)×5=116×5=580 kg= (36 + 80) \times 5 = 116 \times 5 = 580\text{ kg}.
Total cotton =(60+60)×5=120×5=600 kg= (60 + 60) \times 5 = 120 \times 5 = 600\text{ kg}.
Combining the hourly outputs from both machines and multiplying by the total duration of 5 hours.
4
Compute and simplify the ratio of total wool to total cotton.
\text{Ratio} = \frac{580}{600} = \frac{29}{30},whichisexpressedas, which is expressed as 29 : 30$.
Dividing both terms of the ratio by their greatest common divisor, 20.

Key Concept

Combining weighted rates across multiple ratio-based sub-components
Estimated Time:2m 0s
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