In a motor of 120 machine parts. 5% parts were defective. In an other motor of 80 machine parts, 10% parts were defective. For the two motors considered together, the percentage of defective machine parts was

Options

A. 7
B. 6.5
C. 7.5
D. 8

Answer

To find the percentage of defective machine parts for the two motors combined, we can follow these steps:

### Step 1: Calculate the number of defective parts in the first motor.
- The first motor has 120 machine parts, and 5% of them are defective.
- Number of defective parts = (5/100) * 120 = 6 parts.

### Step 2: Calculate the number of defective parts in the second motor.
- The second motor has 80 machine parts, and 10% of them are defective.
- Number of defective parts = (10/100) * 80 = 8 parts.

### Step 3: Calculate the total number of defective parts from both motors.
- Total defective parts = Defective parts from first motor + Defective parts from second motor.
- Total defective parts = 6 + 8 = 14 parts.

### Step 4: Calculate the total number of machine parts from both motors.
- Total machine parts = Machine parts in first motor + Machine parts in second motor.
- Total machine parts = 120 + 80 = 200 parts.

### Step 5: Calculate the percentage of defective parts for both motors combined.
- Percentage of defective parts = (Total defective parts / Total machine parts) * 100.
- Percentage of defective parts = (14 / 200) * 100 = 7%.

### Final Answer:
The percentage of defective machine parts for the two motors considered together is **7%**.

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