To find out how many drinks Colin can make during his 90-minute shift, we first need to determine his rate of making drinks.
Colin made 4 drinks in 12 minutes. To find his rate in drinks per minute, we can divide the number of drinks by the time taken:
\[ \text{Rate} = \frac{\text{Number of drinks}}{\text{Time in minutes}} = \frac{4 \text{ drinks}}{12 \text{ minutes}} = \frac{1 \text{ drink}}{3 \text{ minutes}} \]
Now, we need to calculate how many drinks Colin can make in 90 minutes. Since he makes 1 drink every 3 minutes, we can find the total number of drinks by dividing the total time by the time it takes to make one drink:
\[ \text{Total drinks} = \frac{90 \text{ minutes}}{3 \text{ minutes per drink}} = 30 \text{ drinks} \]
Therefore, Colin will make 30 drinks during his shift.