Question

From the failure data of electronics components presented here, which statement is true?

• A. Integrated circuits and Printed circuit boards are more reliable.
• B. Capacitors are more reliable than pictures tubes.
• C. Higher number of component failures is likely to be due to picture tubes.
• D. The least reliable component is Hybrid Micro circuits.
• A. Pictures tubes
• B. Capacitors
• C. Integrated circuits
• D. Printed Circuits boards
• A. Printed circuits boards and hybrid micro circuits
• B. Capacitors and integrated circuits
• C. Pictures tubes and signal devices
• D. Signal devices and capacitors
• A. 12, 4, 3
• B. 12, 5, 4
• C. 5, 12, 4
• D. 12, 4, 4

Answer 1

The Correct Option is D

Step 1 — Recall the data from the bar chart:
Failure rate per thousand units is given as:
Picture Tubes = 15,
Signal Devices = 16,
Capacitors = 20,
Integrated Circuits = 30,
Printed Circuits = 33,
Hybrid Micro Circuits = 40.

Step 2 — Understand what “least reliable” means:
Reliability of a component is inversely proportional to its failure rate.
⇒ Higher the failure rate, lower the reliability.
⇒ Lower the failure rate, higher the reliability.

Step 3 — Identify the component with the maximum failure rate:
From the given data:
• Picture Tubes have only 15 failures per thousand.
• Hybrid Micro Circuits have 40 failures per thousand.
Clearly, 40 is the highest among all values.

Step 4 — Conclude:
Since Hybrid Micro Circuits have the maximum failure rate (40 per thousand), they are the least reliable component.

Final Answer:
The correct option is (D): The least reliable component is Hybrid Micro Circuits.

Answer 2

Step 1 — Recall the failure rate of Signal Devices:
From the bar chart data:
Failure rate of Signal Devices = 16 per thousand.

Step 2 — Calculate 25% more than this value:
25% of 16 = (25/100) × 16 = 4.
Now add this to the original value:
16 + 4 = 20.
So, the required failure rate is 20 per thousand.

Step 3 — Match with the component values:
From the chart:
• Capacitors = 20 per thousand.
• This exactly matches the calculated value.

Step 4 — Conclude:
The component with a failure rate 25% more than Signal Devices is Capacitors.

Final Answer:
The correct option is (B): Capacitors.

Answer 3

Step 1 — Interpret the question carefully:
The company wants to decide priority for investment in improving component manufacturing units.
Generally, the lowest priority will be given to those components which already have high reliability and low failure rates, because they do not need urgent improvement.

Step 2 — Recall the failure rate data:
• Picture Tubes = 15 per thousand
• Signal Devices = 16 per thousand
• Capacitors = 20 per thousand
• Integrated Circuits = 30 per thousand
• Printed Circuits = 33 per thousand
• Hybrid Micro Circuits = 40 per thousand

Step 3 — Identify the most reliable components:
Reliability is highest when failure rate is lowest.
Among all, Picture Tubes (15) and Signal Devices (16) have the lowest failure rates.
Thus, these are the most reliable components.

Step 4 — Decision on investment priority:
Since these components already perform well with minimum failures, the company does not need to invest much in improving them.
Therefore, these should be given the lowest priority for investment in changes or additions.

Final Answer:
The correct option is (C): Picture Tubes and Signal Devices.

Answer 4

Step 1 — Recall the failure rates from the chart:
• Integrated Circuits = 30 failures per thousand
• Capacitors = 20 failures per thousand
• Printed Circuits = 33 failures per thousand

Step 2 — Formula to calculate spares required:
Expected number of failures = (Failure rate per 1000) × (Number of equipments) / 1000.
This gives how many spares are needed to minimize downtime.

Step 3 — Calculate for each component:
(1) Integrated Circuits:
Number of equipments = 400
Failure rate = 30 per 1000
Failures = (30/1000) × 400 = 12.
⇒ Spares required = 12.

(2) Capacitors:
Number of equipments = 240
Failure rate = 20 per 1000
Failures = (20/1000) × 240 = 4.8 ≈ 5.
⇒ Spares required = 5.

(3) Printed Circuits:
Number of equipments = 120
Failure rate = 33 per 1000
Failures = (33/1000) × 120 = 3.96 ≈ 4.
⇒ Spares required = 4.

Step 4 — Final Result:
Spares required are:
Integrated Circuits = 12,
Capacitors = 5,
Printed Circuits = 4.

Final Answer:
The correct option is (B): 12, 5, 4.