Study the given table and answer the question that follows.

The table shows the yearly production (in thousands) of scooters in five different factories (P, Q, R, S and T) from 1985 to 1989.

Factory	1985	1986	1987	1988	1989
P	20	15	24	13	17
Q	16	23	41	20	15
R	14	21	30	16	12
S	25	17	15	12	22
T	40	32	39	41	35
Total	115	108	149	102	101

In which year was the production of scooters in all factories equal to the yearly average number of scooters produced from 1985 to 1989?

The correct answer is 1985.

To find the year in which the total production of scooters across all factories was equal to the yearly average production from 1985 to 1989, we first need to calculate the average total yearly production across all five years.

Step 1: Identify the total production for each year
From the given table, the total production of scooters (in thousands) in all factories (P, Q, R, S, and T) for each year is as follows:

• 1985: 115
• 1986: 108
• 1987: 149
• 1988: 102
• 1989: 101

Step 2: Calculate the total production for all 5 years combined

$\text{Total Production}=115+108+149+102+101=575$

Step 3: Calculate the yearly average number of scooters produced
There are 5 years in total (1985 to 1989). Divide the combined total production by 5:

$\text{Yearly Average}=\frac{575}{5}=115$

Step 4: Match the average with the table values
The yearly average production is 115 (in thousands). Looking at the table, the total production in the year 1985 was exactly 115 (in thousands).

Therefore, in the year 1985, the production of scooters in all factories was equal to the yearly average number of scooters produced from 1985 to 1989.