Answer :
To calculate the number of Social Security credits that Mike earned in 1980, we need to follow these steps:
Step 1: Calculate Mike's total annual earnings.
Mike earned $55 per week. There are 52 weeks in a year. So, his total annual earnings are calculated as follows:
Total annual earnings = weekly earnings × number of weeks in the year
Total annual earnings = $55 × 52
Total annual earnings = $2,860
Step 2: Calculate the number of credits Mike earned.
The amount of earnings required to earn one Social Security credit in 1980 was $290. We can calculate the number of credits Mike earned by dividing his total annual earnings by the amount required to earn one credit.
Number of credits = total annual earnings ÷ earnings required per credit
Number of credits = $2,860 ÷ $290
Number of credits = 9.862068965517241
Step 3: Round the number of credits to two decimal places.
We are instructed to round the number of credits to two decimal places.
Number of credits (rounded) = 9.86
Therefore, Mike earned 9.86 Social Security credits in 1980.