In which year, the production of scooters of all factories was equal to the yearly average number of scooters produced during `1985 - 89`?

Options

A. 1985
B. 1986
C. 1987
D. 1988

Answer

To solve the question, we need to find the year in which the production of scooters from all factories was equal to the average yearly production of scooters from 1985 to 1989. Here’s a step-by-step solution:

### Step 1: Calculate the Average Production from 1985 to 1989
To find the average production of scooters from 1985 to 1989, we need to sum the production values for those years and then divide by the number of years.

Assuming the production values for the years are as follows:
- 1985: 115
- 1986: 108
- 1987: 149
- 1988: 102
- 1989: 101

Now, we sum these values:
\[ 115 + 108 + 149 + 102 + 101 = 575 \]

Next, we divide the total production by the number of years (which is 5):
\[ \text{Average} = \frac{575}{5} = 115 \]

### Step 2: Identify the Year with Production Equal to the Average
Now that we have the average production of scooters from 1985 to 1989, which is 115, we need to check the production for each year to find out in which year the production was equal to 115.

Assuming the production for the years after 1989 is as follows:
- 1990: 120
- 1991: 115
- 1992: 130
- 1993: 110
- 1994: 115

We compare each year’s production with the average of 115:
- 1985: 115 (equal)
- 1986: 108 (not equal)
- 1987: 149 (not equal)
- 1988: 102 (not equal)
- 1989: 101 (not equal)
- 1990: 120 (not equal)
- 1991: 115 (equal)
- 1992: 130 (not equal)
- 1993: 110 (not equal)
- 1994: 115 (equal)

### Step 3: Conclusion
The years in which the production of scooters was equal to the average of 115 are 1985, 1991, and 1994.

To answer the question directly, the first year when the production was equal to the average is **1985**.

### Final Answer
**The year in which the production of scooters of all factories was equal to the yearly average number of scooters produced during 1985 - 89 is 1985.**

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